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          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
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          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SelfInsuranceReserve" xlink:label="us-gaap_SelfInsuranceReserve"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany" xlink:label="dei_EntityEmergingGrowthCompany"/>
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          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FederalHomeLoanBankAdvancesMember" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20260630.xsd#fusb_ChiefInformationAndConsumerBankingOfficerMember" xlink:label="fusb_ChiefInformationAndConsumerBankingOfficerMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20260630.xsd#fusb_ChiefConsumerLendingOfficerMember" xlink:label="fusb_ChiefConsumerLendingOfficerMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20260630.xsd#fusb_ChiefCommercialLendingOfficerMember" xlink:label="fusb_ChiefCommercialLendingOfficerMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20260630.xsd#fusb_ChiefRiskOfficerMember" xlink:label="fusb_ChiefRiskOfficerMember"/>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Interest Payable, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase (decrease) in accrued interest expense</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeRecorded_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income Recorded</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeRecorded_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest income recorded.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Unrealized holding losses arising during the period on effective cash flow hedge derivatives, net of tax benefit of $103 and $0, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding gains (losses) arising during the period on effective cash flow hedge derivatives, net of tax expense (benefit) of $76, ($45), $198 and ($148), respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segments [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, Equal to or Greater than 90 Days Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Equal to or Greater than 90 Days Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Incorporation, State or Country Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Incorporation, State or Country Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position Location, Balance [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-cash transactions:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PassAndCriticizedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pass And Criticized [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PassAndCriticizedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pass And Criticized [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PassAndCriticizedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Pass And Criticized [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing within one year, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablePortfolioSegmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing Receivable Portfolio Segment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablePortfolioSegmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable Portfolio Segment [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans net of unearned income and unamortized deferred fees and costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans net of unearned income and unamortized deferred fees and costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans net of unearned income and unamortized deferred fees and costs.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, 12 months or more, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Current Reporting Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Current Reporting Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Financing Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Financing Receivable [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">US Government Sponsored Agencies [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">US Government Agencies Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Government Agencies Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Recoveries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Loss, Recovery of Bad Debts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate floor contracts two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floor Contracts Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Guarantees, Commitments and Contingencies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash Flow Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Flow Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares Authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other non-interest expense.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Non-Interest Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding gains on securities available-for-sale arising during period, tax expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Operating Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Other Operating Income By Component [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of other operating income by component.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product and Service</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Insured or Guaranteed by Government Authorities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans Insured or Guaranteed by Government Authorities [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value by Liability Class [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indirect Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indirect [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Indirect.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Indirect [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan, fixed interest rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Interest Rate, Stated Percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Long-Term Borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Maturities of Long-Term Debt [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares issued (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShortTermDebtTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Short Term Debt [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShortTermDebtTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts three.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts Three [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Noninterest-Bearing Deposit Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest-bearing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest-Bearing Deposit Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, 12 months or more, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Receivable, Related Parties, Additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Related Parties, Additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Federal funds sold and securities purchased under reverse repurchase agreements fair value disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold and securities purchased under reverse repurchase agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Receivable, Related Parties, Proceeds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Related Parties, Proceeds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after one to five years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year One through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value portion of federal funds sold.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Business Acquisition, Acquiree</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expired, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassification, Comparability Adjustment [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, 60 to 89 Days Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, 60 to 89 Days Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivablesPastDueTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Past Due [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities and shareholders&#8217; equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResidentialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Residential Mortgage-Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResidentialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Residential Mortgage Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total non-interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total non-interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Non-interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options exercisable, end of period, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeveranceCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Severance and personnel expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeveranceCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Severance Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentsToExtendCredit1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments to Extend Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentsToExtendCredit1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments To Extend Credit1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentsToExtendCredit1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loan commitments are legally binding commitments to extend credit to a counterparty under certain terms and conditions.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageParValueAllowedAsCollateral_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage par value allowed as collateral.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageParValueAllowedAsCollateral_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Par Value Allowed as Collateral</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageParValueAllowedAsCollateral_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage par value allowed as collateral.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByBalanceSheetGroupingTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, by Balance Sheet Grouping</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByBalanceSheetGroupingTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, by Balance Sheet Grouping [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Relationship</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Relationship [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scheduled of Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Costs [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalents, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, 30 to 59 Days Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, 30 to 59 Days Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill And Other Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill And Other Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Goodwill and other intangible assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgedStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledged Status [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Foreclosed real estate owned, fair value less disposal costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreclosed Real Estate Owned Fair Value Less Disposal Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The fair value less estimated costs to sell of foreclosed residential real estate held by the Company as of the balance sheet date.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Goodwill, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Goodwill, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Goodwill, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Goodwill</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Effective Income Tax Rate Reconciliation, Percent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Effective Income Tax Rate Reconciliation, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Employee Stock Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Fiscal Year Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs fiscal year before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2025</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransferToOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransferToOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate Owned, Transfer to Real Estate Owned</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateNetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Net Income Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateNetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate net income loss.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateNetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquipmentFinancingLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equipment Financing Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquipmentFinancingLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equipment Financing Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquipmentFinancingLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Equipment financing leases member</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional paid-in capital</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid in Capital, Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossLosses_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Gross losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Gross Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate gross losses.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfStates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of states</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfStates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of States</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfStates_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of states conducting lending of loan portfolio.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Non Residential Commercial Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Secured by non residential commercial real estate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by Non-residential Commercial Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basis of Presentation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Significant Accounting Policies [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonperformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Non-performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonperformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Nonperforming Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonperformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Nonperforming Financial Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Reclassification of unrealized gains on terminated derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassification of unrealized gains on terminated derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Reclassification of unrealized gains on terminated derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Asset, Useful Life</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and other intangible assets amortized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gains Losses On Sales Of Premises Equipment And Other Real Estate Held For Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Gains losses on sales of premises equipment and other real estate held for sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net loss on premises and equipment and other real estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Granted (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposits, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Earnings Per Share, Basic and Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetInvestmentHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Investment Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SpecialMentionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Special Mention</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SpecialMentionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Special Mention [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturities of Investment Securities Available-for-Sale and Held-to-Maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments Classified by Contractual Maturity Date [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Earnings Per Share, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic net income per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of interest rate swap contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Interest Rate Swap Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of interest rate swap contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, gross unrealized gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment in Federal Home Loan Bank Stock, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other comprehensive income (loss), reclassification adjustment net gains on cash flow hedge derivatives realized in net income, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other comprehensive income (loss), reclassification adjustment net gains on cash flow hedge derivatives realized in net income, net of tax.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustment for net gains on cash flow hedge derivatives realized in net income, net of tax benefit of $5, $0, $5 and $0, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Reclassification adjustments on cash flow hedge derivatives realized in net income, net of tax benefit of $12, $12, $24 and $24, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Cap One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate cap one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Losses Write Offs Three Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs three years before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2023</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial Portfolio Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Outstanding, beginning of period (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Options outstanding, end of period (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseDirectorsFees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Directors fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseDirectorsFees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Director Fee</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share based compensation arrangement by share based payment award, equity instruments other than options, released from restriction in period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share-based compensation arrangement by share-based payment award equity instruments other than options released from restriction in period.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Released from restriction (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Operating Lease, Lease Income, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Lease Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustments to reconcile net income to cash provided by operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Designation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Designation [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgesLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments and Hedges, Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgesLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative Instruments and Hedges, Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgesLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative instruments and hedges, cash payment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgingPurposeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledging Purpose [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Income, Deposits with Financial Institutions, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income, Deposits with Financial Institutions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on deposits in banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseRemainingTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, Operating Lease, Remaining Term of Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseRemainingTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Remaining Term Of Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseRemainingTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The remaining term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidationItemsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidation Items [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shareholders&#8217; equity:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity, Attributable to Parent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperatingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperatingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Operating [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Designation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Designation [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Retained Earnings (Accumulated Deficit), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retained earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings (Accumulated Deficit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-accruing Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, Prior</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Five Or More Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs five or more years before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NatureOfOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">General</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NatureOfOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Nature of Operations [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held to maturity, allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Held-to-maturity securities allowance for credit loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral dependent loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Dependent Loans Measurement Input</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collateral dependent loans measurement input.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Financing receivable, allowance for credit loss, writeoff, after recovery.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInceptionDates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative, start date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInceptionDates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Inception Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Awards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInFederalFundsSold_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Federal Funds Sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInFederalFundsSold_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net decrease in federal funds sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Notes to Financial Statements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income tax disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments of Dividends</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments of Dividends, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Dividends paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedAssetsAcquiredInSettlementOfLoans_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets acquired in settlement of loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedAssetsAcquiredInSettlementOfLoans_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreclosed Assets Acquired In Settlement Of Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedAssetsAcquiredInSettlementOfLoans_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the amount of foreclosed assets acquired in settlement of loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">OREO and other assets held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Other Assets Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate and other assets held-for-sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeasesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Leases [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditRiskParticipationAgreementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Risk Participation Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditRiskParticipationAgreementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit risk participation agreements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted Average Number of Shares Outstanding, Diluted, Adjustment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dilutive shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Diluted, Adjustment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee Lease Description [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Lease, Description [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairmentOfRealEstate_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairmentOfRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impairment of Real Estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product and Service</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Operating Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Other Operating Cost and Expense, by Component [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructured Loan Modified through Extended Maturity and Payment Schedule Modification [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructured Loan Modified Through Extended Maturity And Payment Schedule Modification [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Member stands for restructured loan modified through extended maturity and payment schedule modification.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Federal Funds Sold and Securities Purchased under Agreements to Resell, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold and Securities Purchased under Agreements to Resell</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold and securities purchased under reverse repurchase agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Income Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LIABILITIES AND SHAREHOLDERS&#8217; EQUITY</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash provided by operating activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubstandardMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Substandard</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubstandardMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Substandard [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Foreclosed real estate other expense net of gain or loss on sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreclosed Real Estate Other Expense Net Of Gain Or Loss On Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other real estate/foreclosure expense, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swap one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteoffsNetAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain On Sales Of Premises And Equipment And Other Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Gain on sales of premises and equipment and other assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gain on sales of premises and equipment and other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Granted, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingRelationshipDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Relationship</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingRelationshipDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Relationship [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Three</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2029</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Cumulative Basis Adjustments for Fair Value Hedges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net accretion of securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortization of Debt Discount (Premium)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://fasb.org/us-gaap/role/label/axisDefault">Portion at Fair Value Measurement [Member] [Default]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Portion at Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Fair Value Assumptions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, after Year Four</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee, operating lease, liability, to be paid, after year four.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2031 and thereafter</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShorttermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShorttermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsumerPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsumerPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Consumer Portfolio Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsumerPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consumer Portfolio Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Supplemental disclosures:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplemental Cash Flow Information [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BranchRetailMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Branch Retail [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BranchRetailMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Branch Retail [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BranchRetailMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents branch retail loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative Asset, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other assets - derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral pledged in excess available to utilize additional credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank Advances General Debt Obligations Disclosures Excess Of Collateral Available To Utilize Additional Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of collateral pledged in excess available to utilize additional credit.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other non-interest income member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Non-Interest Income [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Non-Interest Income [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position Location, Balance [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets Measured on Nonrecurring Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurements, Nonrecurring [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease right-of-use assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Right-of-Use Asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitment required for evaluating individually at management discretion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitment Required for Evaluating Individually At Management Discretion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Commitment required for evaluating individually at management discretion.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of investment securities, available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to Acquire Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net change in fair value of securities available-for-sale, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Reclassification adjustment for net gains on securities available-for-sale realized in net income, net of tax expense of $113, $-, $113 and $-, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputComparabilityAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input, Comparability Adjustment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputComparabilityAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input, Comparability Adjustment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonfarmNonresidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured By Non-farm Non residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonfarmNonresidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Nonfarm Nonresidential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonfarmNonresidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by non-farm, non-residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income Taxes Paid, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes Paid, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments, Debt and Equity Securities [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositsInBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest-bearing deposits in banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositsInBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest-Bearing Deposits in Banks and Other Financial Institutions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedParties_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Loans and Leases Receivable, Related Parties, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedParties_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Loans and Leases Receivable, Related Parties, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedParties_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Related Parties</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net increase (decrease) in cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Income, Operating, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and core deposit intangible, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Intangible Assets, Net (Including Goodwill)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Impact of common stock share repurchases (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Repurchased and Retired During Period, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after five to ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 5 through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Par or Stated Value Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfAdoptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PaycheckProtectionProgramMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Paycheck Protection Program [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PaycheckProtectionProgramMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Paycheck Protection Program [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PaycheckProtectionProgramMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Paycheck protection program.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Credit Quality Indicator [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing Receivable Recorded Investment [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Other Operating Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Operating Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase (decrease) in other liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Available-for-sale, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt securities held to maturities in unrealized loss position</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Held-to-maturity, less than 12 months, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Available-for-sale, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment securities available-for-sale, at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment securities available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Investment securities available-for-sale, at fair value (amortized cost $168,469 and $169,037; net of allowance for credit losses of $- and $-)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Income [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherRestructuringCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherRestructuringCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Restructuring Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instruments [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Exercised (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DoubtfulMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Doubtful [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Notes to Financial Statements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditLossesOnUnfundedLendingCommitmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit losses on unfunded lending commitments.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditLossesOnUnfundedLendingCommitmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Losses on Unfunded Lending Commitments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimate of Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Estimate of Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Notional amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Notional Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Notional Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instrument Performance Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument Performance Status [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Long-Term Debt Instruments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to FHLB Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To F H L B Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to FHLB advances.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap Three [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swap three.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TwoYearTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Two Year Term Loan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TwoYearTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Year Term Loan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TwoYearTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two year term loan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Quarterly Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Quarterly Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherCostAndExpenseOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherCostAndExpenseOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Cost and Expense, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReceivablesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Receivables [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Unvested shares, beginning of period (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Unnvested shares, end of period (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Proceeds from (Repayments of) Short-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from (Repayments of) Short-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net increase in short-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instrument Performance Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument Performance Status [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, gross unrealized gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accrued Interest Receivable, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Increase in accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Internal Credit Assessment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Internal Credit Assessment [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Accrued Interest, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfessionalFees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Professional Fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfessionalFees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fees for professional services</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectConsumersMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Indirect consumers.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectConsumersMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indirect Consumers [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectConsumersMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indirect Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Comprehensive Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Net of Tax [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other comprehensive income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other comprehensive (loss) income :</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToVariableRateMoneyMarketDepositAccountsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to Variable-Rate Money Market Deposit Accounts [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToVariableRateMoneyMarketDepositAccountsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To Variable Rate Money Market Deposit Accounts [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToVariableRateMoneyMarketDepositAccountsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to variable-rate money market deposit accounts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Held-to-maturity, 12 months or more, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net interest income after provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net interest income after provision</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense), after Provision for Loan Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfRevenueExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue, Product and Service [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by real estate 1-to-4-family residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Real Estate 1 To 4 Family Residential Properties Member</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by Real Estate 1-4 Family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expired (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Expirations in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Employees.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employees [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employees [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Sale of Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from the sale of investment securities, available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CorrespondentBanksMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Correspondent Banks [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CorrespondentBanksMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Correspondent Banks [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CorrespondentBanksMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Correspondent Banks [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">AOCI Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">AOCI Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Accumulated Other Comprehensive Loss [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Derivative liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative Liability, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities - credit risk participation agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite-Lived Intangible Assets, Major Class Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Common, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury Stock, shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AcceptanceLoanCompanyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ALC [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AcceptanceLoanCompanyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Acceptance Loan Company [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AcceptanceLoanCompanyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents a segment of the company.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reissuance of treasury stock as compensation (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Shares, Treasury Stock Reissued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swap two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeAssetsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Derivative Assets, at Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeAssetsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest rate derivative contracts, assets at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeAssetsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Derivative contracts, assets at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate floors.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturity date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Maturity Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Minimum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Granted, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instrument</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest on borrowings.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest On Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2025</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by 1-4 Family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By1 To4 Family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by 1-to-4-family residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortization of intangible assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortization of Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Software amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 3 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 3 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsNonrecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Nonrecurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Assets Measured on Recurring Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets Measured on Recurring Basis [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral dependent loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Dependent Loans Fair Value disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collateral dependent loans fair value disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Activities Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Impact of common stock share repurchases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Repurchased and Retired During Period, Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableNonaccrualTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MinimumCommitmentRequiredForEvaluatingIdividually_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum commitment required for evaluating idividually</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MinimumCommitmentRequiredForEvaluatingIdividually_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Minimum Commitment Required for Evaluating Idividually</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MinimumCommitmentRequiredForEvaluatingIdividually_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Minimum commitment required for evaluating idividually.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Balance (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Balance (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares, Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities - credit risk participation agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities - Credit Risk Participation Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities - credit risk participation agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Loan Portfolio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest expense:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Operating and Nonoperating [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Less:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseRenewalTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Renewal Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseRenewalTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, Operating Lease, Renewal Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustment for net gains on securities available-for-sale realized in net income, net of tax expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Decrease in Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Decrease in Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net decrease in federal funds sold and securities purchased under reverse repurchase agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Unvested shares, end of period, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Unvested shares, beginning of period, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EurodollarMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Eurodollar [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of stock-based compensation plans, net (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total operating lease liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impaired loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impaired Loans Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value portion of impaired loans by an entity as a result of past transactions or events.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and leases held for investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Remaining unrealized gains associated with terminated derivatives.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Remaining Unrealized Gains Associated With Terminated Derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Remaining unrealized gains associated with terminated derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable interest rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Basis Spread on Variable Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtMaximumMonthEndOutstandingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum month-end balance during the period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtMaximumMonthEndOutstandingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt Maximum Month End Outstanding Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtMaximumMonthEndOutstandingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Long term debt maximum month end outstanding amount.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Short-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Loss Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Loss Status [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Cap Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate cap two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reissuance of treasury stock as compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Treasury Stock Reissued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Securities, Available-for-sale, Restricted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Restricted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaturityPeriodOfFederalFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturity Period of Federal Funds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaturityPeriodOfFederalFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maturity Period Of Federal Funds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaturityPeriodOfFederalFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Maturity period of federal funds.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee Lease Description [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Lease, Description [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prior</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Originated, More than Five Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense), Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Segment net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Nonaccrual loans with no allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Financing Receivable, before Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Held-to-maturity, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">2031 and thereafter</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment securities held-to-maturity, at amortized cost, net of allowance for credit losses of $- and $-, (fair value 2026 - $364, 2025 - $449)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accruing loans past due 90 days or more amounted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, 90 Days or More Past Due, Still Accruing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Debt, Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted Average Number of Shares Outstanding, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditDerivativesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Derivatives [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditDerivativesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit derivatives.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Losses, Writeoff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Current period gross charge-offs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSettlementOfDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from settlement of derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSettlementOfDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Settlement of Derivative Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSettlementOfDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from settlement of derivative contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Four Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs four years before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2022</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-sale, 12 months or more, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">FUSB [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segments [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsTaxNoncontrollingInterest1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net change in fair value of derivative instruments, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsTaxNoncontrollingInterest1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax, Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pledged as Collateral [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Pledged as Collateral [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Compensation Liability, Current and Noncurrent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Liability, Current and Noncurrent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Liability, Current and Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansReceivableFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans Receivable, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansReceivableFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans, net of allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustments on cash flow hedge derivatives realized in net income, tax benefit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Long-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan, aggregate principal balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Securities Sold under Agreements to Repurchase, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Securities Sold under Agreements to Repurchase, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Securities Sold under Agreements to Repurchase</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateTerms_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest rate, description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateTerms_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Interest Rate Terms</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetDeferredTaxAssetsLiabilitiesIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net deferred tax asset increased</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetDeferredTaxAssetsLiabilitiesIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Deferred Tax Assets Liabilities Increase Decrease</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetDeferredTaxAssetsLiabilitiesIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Net deferred tax assets liabilities increase decrease.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income tax disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Stockholders' Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CorporateNoteSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Corporate Notes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CorporateNoteSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Corporate Note Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate floor contracts one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floor Contracts One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Held-to-maturity, gross unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfRestructuringDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Type of Restructuring</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfRestructuringDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Type of Restructuring [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Internal Credit Assessment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Internal Credit Assessment [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Common [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Treasury Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Financing Receivable, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Financing Receivable, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for credit loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value of Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosures [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeOther_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeOther_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other income, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeOther_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Income, Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Loan and Lease Losses and Recorded Investment in Loans by Loan Classification and by Impairment Evaluation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Loan and Lease Losses and Recorded Investment in Loans by Loan Classification and by Impairment Evaluation [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of loan and lease losses and recorded investment in loans by loan classification and by impairment evaluation table text block.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Transition adjustment increase in allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Transition adjustment increase in loan loss reserves</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Transition adjustment increase in loan loss reserves.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments and Hedging Activities Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other income and expenses table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CarryingAmountOfLoansByCreditQualityIndicatorAndYearOfOriginationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Carrying Amount of Loans by Credit Quality Indicator and Year of Origination</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CarryingAmountOfLoansByCreditQualityIndicatorAndYearOfOriginationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Carrying Amount Of Loans By Credit Quality Indicator And Year Of Origination [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CarryingAmountOfLoansByCreditQualityIndicatorAndYearOfOriginationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Carrying amount of loans by credit quality indicator and year of origination.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingOtherItemAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Other Segment Item, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingOtherItemAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other segment items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Other Operating Assets, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Operating Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Decrease in other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Operating and Nonoperating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Investments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Investments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of amortized cost basis of collateral dependent loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Amortized Cost Basis of Collateral Dependent Loans [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Schedule of Amortized Cost Basis of Collateral Dependent Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">As a percentage of total loans, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loans And Leases Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loans and leases current.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan Restructuring Modification</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loan Restructuring Modification [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Available Unused Lines of Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advance, Branch of FHLBank [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, less than 12 months, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Treasury Stock, Value, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less treasury stock: 2,495,917 and 2,247,607 shares at cost, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleOfOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Sales proceeds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleOfOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Sale of Other Real Estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesLongTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-Term Federal Home Loan Bank Advances, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesLongTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Federal Home Loan Bank advances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesLongTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Federal Home Loan Bank Advances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related and Nonrelated Parties [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year One, Originated, Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2026</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorStockEquivalentShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average director stock equivalent shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorStockEquivalentShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted average director stock equivalent shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorStockEquivalentShares_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average director stock equivalent shares.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollateralAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Held [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndDueFromBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash and Due from Banks, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndDueFromBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and due from banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndDueFromBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Due from Banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PastDueFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Aging Analysis of Past Due Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PastDueFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Past Due [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of reportable segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Reportable Segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Deposits, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Investment Securities Available-for-Sale and Held-to-Maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Investment Securities Available For Sale And Held To Maturity Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tabular disclosure of investment securities available for sale and held to maturity.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest expense:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Expense [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of interest rate swap contracts terminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Interest Rate Swap Contracts Terminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of interest rate swap contracts terminated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RealEstate1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RealEstate1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RealEstate1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to real estate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income before income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NonEmployeeDirectorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Non-employee directors.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NonEmployeeDirectorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Non Employee Directors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NonEmployeeDirectorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-employee Directors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CompensationRelatedCostsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Compensation Related Costs [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgingPurposeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledging Purpose [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSaleOfPremisesAndEquipmentOtherRealEstateAndRepossessions_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from sale of premises and equipment,other real estate and repossessions.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSaleOfPremisesAndEquipmentOtherRealEstateAndRepossessions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Sale of Premises and Equipment, Other Real Estate and Repossessions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSaleOfPremisesAndEquipmentOtherRealEstateAndRepossessions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from the sale of premises and equipment, other real estate and repossessions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetNotPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetNotPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Not Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash and cash equivalents, beginning of period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Cash and cash equivalents, end of period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CoreDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Core Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CoreDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Core Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Paid, Excluding Capitalized Interest, Operating Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Basis [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherOperatingIncomeAndExpenseTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Operating Income and Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherOperatingIncomeAndExpenseTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Operating Income and Expense [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based payment arrangement, expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesGainLossRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income Loss Available For Sale Securities Gain Loss Realized in Net Income Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesGainLossRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other comprehensive income loss available for sale securities gain loss realized in net income net of tax.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesGainLossRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustment for net gains on securities available-for-sale realized in net income, net of tax expense of $113, $-, $113 and $-, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_TitleOfIndividualAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title and Position [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Hierarchy and NAV</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Long term debt weighted average remaining maturity term.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt Weighted Average Remaining Maturity Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average remaining maturity (in years)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest on deposits member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest On Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options exercisable, end of period (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ThePeoplesBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">The Peoples Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ThePeoplesBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">The Peoples Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ThePeoplesBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information regarding The Peoples Bank.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forward Interest Rate Swap Contracts [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Loss Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Loss Status [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization consolidation and presentation of financial statements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Organization Consolidation And Presentation Of Financial Statements [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable rate, description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Description of Variable Rate Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cumulative Effect Adjustment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cumulative Effect, Period of Adoption, Adjustment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingency Nature</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Nature [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoanPortfolio_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of Loan Portfolio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoanPortfolio_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loan Portfolio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoanPortfolio_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loan portfolio.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingency, Nature</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency, Nature [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentInterestRateIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Derivative instrument, interest rate, increase (decrease).</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentInterestRateIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instrument, Interest Rate, Increase (Decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentInterestRateIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative instrument, interest rate, increase (decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CompensationAndEmployeeBenefitPlansTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CompensationAndEmployeeBenefitPlansTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Compensation and Employee Benefit Plans [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollectionAndRecoveries_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collection and recoveries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollectionAndRecoveries_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collection And Recoveries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollectionAndRecoveries_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collection and recoveries.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Realized Gain (Loss), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net gain on sale and prepayment of investment securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net gain on sales and prepayments of investment securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Realized Gain (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NondesignatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Not Designated as Hedging Instrument [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NondesignatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives Not Designated as Hedging Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NondesignatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Derivatives Not Designated as Hedging Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, Aging</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Aging [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Deposits, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net increase (decrease) in deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Commitment and Contingent Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Fair Value, off-Balance-Sheet Risks [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing within one year, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing within one year, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Two</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2028</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Instruments Gain Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments, Gain (Loss) [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Derivative Liabilities, at Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Derivative contracts, liabilities at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities - interest rate swaps</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable Credit Quality Indicators [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases By Credit Quality Indicators</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Restricted Stock Award [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureOfEntitysReportableSegmentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments and contingent liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosure, off-Balance-Sheet Risks, Amount, Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortized cost basis of closed portfolios used in hedging relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortized Cost Basis Of Closed Portfolios Used In Hedging Relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amortized cost basis of closed portfolios used in hedging relationships.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-sale, less than 12 months, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Diluted shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Securities Act File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to fixed rate indirect consumer loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To Fixed Rate Indirect Consumer Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related To Fixed Rate Indirect Consumer Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding gains (losses) on securities available-for-sale arising during period, net of tax expense (benefit) of $259, $124, $930, and $101, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Unrealized holding (losses) gains on securities available-for-sale arising during period, net of tax (benefit) expense of ($96), $259, ($368), and $930, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Assets, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CoverAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_CumulativeEffectPeriodOfAdoptionAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cumulative Effect, Period of Adoption [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubordinatedDebtMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subordinated Debt [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubordinatedDebtMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subordinated Debt [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, Aging</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Aging [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation and amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation And Amortization Of Property Plant And Equipment And Computer Programs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Depreciation and amortization of property, plant, and equipment and computer programs.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative, Gain (Loss) on Derivative, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated Fair Value Gain (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Gain (Loss) on Derivative, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetGainOnSalesAndPrepaymentsOfInvestmentSecurities_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net gain on sales and prepayments of investment securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetGainOnSalesAndPrepaymentsOfInvestmentSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net gain on sales and prepayments of investment securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetGainOnSalesAndPrepaymentsOfInvestmentSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Net gain on sales and prepayments of investment securities.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_Customer-RelatedInterestRateSwapsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Customer-Related Interest Rate Swaps One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_Customer-RelatedInterestRateSwapsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Customer-related interest rate swaps one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate Acquired Through Foreclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other real estate owned</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasurySecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">US Treasury Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasurySecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Treasury Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairedFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Individually Evaluated, as well as any Related Allowance for Loans and Lease Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairedFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impaired Financing Receivables [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Nonvested Restricted Stock Shares Activity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted Stock Award Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue from Contract with Customer, Including Assessed Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue from Contract with Customer, Including Assessed Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StandbyLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Standby Letters of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StandbyLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Standby Letters of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnusedLinesOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unused lines of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnusedLinesOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unused lines of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from maturities and prepayments of investment securities, held-to-maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term Debt, Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt, Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other income and expenses.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgedStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledged Status [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pre-tax charges of restructuring</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term Debt, Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt, Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Investments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Investments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounting Standards Recently Adopted/ Not Yet Adopted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Future Minimum Operating Lease Payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments, Gain (Loss) [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other-than-temporary Impairment Loss, Debt Securities, Available-for-Sale, Recognized in Earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Two Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs two years before latest fiscal year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2024</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, award vesting period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Provision for Loan and Lease Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial And Industrial Loans And Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Commercial and industrial loans and leases.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Commercial and industrial loans and leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial and Industrial Loans and Leases ("C&amp;I") [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Carrying Amount [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reported Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SuppliesAndPostageExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplies and Postage Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SuppliesAndPostageExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Supplies and Postage Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SuppliesAndPostageExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Postage, stationery and supplies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">As a percentage of total loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loans And Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loans and leases.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Payments Related To Tax Withholding For Share Based Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from payments related to tax withholding for share based compensation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net share-based compensation transactions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Common Stock, Shares, Outstanding, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Common Stock, Shares, Outstanding, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares outstanding (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtAverageAmountOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Average balance during the period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtAverageAmountOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Average Amount Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateOwnedTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Real Estate Owned and Repossessed Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateOwnedTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate Owned [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Tax Assets, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Tax Assets, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestAndFeesOnLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest and Fees on Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestAndFeesOnLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest And Fees On Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestAndFeesOnLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest and fees on Loans member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsCustomerRelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Assets - Customer-Related Interest Rate Swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsCustomerRelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other assets customer related interest rate swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsCustomerRelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets - customer-related interest rate swaps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Liabilities - Customer-Related Interest Rate Swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other liabilities customer related interest rate swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities - customer-related interest rate swaps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Investment securities held-to-maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Held-to-maturity, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Held-to-maturity, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringChargesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expense Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringChargesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Charges [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Leases [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Repurchases of common stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for Repurchase of Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total comprehensive income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net unrealized gain</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrealized Gain (Loss) on Derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Cash Flows [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Option Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Option, Activity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Direct consumer member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Direct [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Direct Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Direct Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Construction, land development and other land loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Construction, Land Development and Other Land Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Construction Land Development And Other Land Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to construction, land development and other land loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableNonaccrualStatusLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateSwapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts and Financing Receivables [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill And Other Intangible Asset [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill And Other Intangible Asset [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Goodwill and other intangible asset.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, options, outstanding, intrinsic value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Intangible Assets, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other intangible assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement with Individual, Share-Based Payments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating cash flows from operating leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Provision for Loan, Lease, and Other Losses, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Provision for Loan, Lease, and Other Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativesFairValueLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives Fair Value [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativesFairValueLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivatives, Fair Value [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity securities accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASSETS</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank stock, at cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TerminationOfTechnologyContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Termination of technology contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TerminationOfTechnologyContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Termination Of Technology Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TerminationOfTechnologyContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Termination of technology contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Activities [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Year Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Year Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Modified in a Troubled Debt Restructuring</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Modified [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_Customer-RelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Customer-related interest rate swaps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_Customer-RelatedInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Customer-Related Interest Rate Swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from investing activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnfundedLoanCommitmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reserve for Unfunded Commitments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnfundedLoanCommitmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unfunded Loan Commitment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnfundedLoanCommitmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Unfunded Lending Commitments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FiveYearTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Five Year Term Loan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FiveYearTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Five Year Term Loan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FiveYearTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Five year term loan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardStartingContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of forward starting contracts terminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardStartingContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of forward starting contracts terminated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Fair Value Off Balance Sheet Risks [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, off-Balance-Sheet Risk [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeMaturityDates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Contract End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeMaturityDates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative, maturity dates</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of stock-based compensation plans, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Cost And Reserve [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Cost and Reserve [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnInvestmentsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Fair Value and Unrealized Loss on Investments for Securities for Which Allowance for Credit Losses has not been Recorded</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnInvestmentsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrealized Gain (Loss) on Investments [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset Acquired With Credit Deterioration [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset Acquired with Credit Deterioration [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InvestmentIntoCapitalSurplus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment into capital surplus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InvestmentIntoCapitalSurplus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Into Capital Surplus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InvestmentIntoCapitalSurplus_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Investment into capital surplus.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalReserveBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Reserve Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalReserveBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Reserve Bank Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalReserveBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">FRB [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosures [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to Interest-Bearing Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to interest-bearing liabilities member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related to Interest-Bearing Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization consolidation and presentation of financial statements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Organization Consolidation And Presentation Of Financial Statements [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2027</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial and Industrial Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial And Industrial Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to commercial and industrial loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Hedging Derivative Instruments' Effect on Company's Interim Condensed Consolidated Statement of Operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Derivative Instruments Effect On Statement Of Operations Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of derivative instruments effect on statement of operations.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-Term Line of Credit, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Line of Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit agreement with related party expired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Credit Risk Participation Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of credit risk participation agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of credit risk participation agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentRiskAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Instrument</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentRiskAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralWithoutRightMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Pledged as Collateral without Right [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in investing activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Private Placement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Private Placement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of office closed</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring And Related Cost Number Of Office Closed</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents number of office closed during period for restructuring and related cost.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PassMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pass [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PassMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pass</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total loans individually evaluated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Loans Individually Evaluated Amortized Cost Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collateral Loans Individually Evaluated Amortized Cost Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments and Hedging Activities Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after one to five years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related and Nonrelated Parties [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available for sale, allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Available-for-sale securities allowance for credit loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2026</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Short-Term Borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Short-Term Borrowings, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LegalEntityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Legal Entity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LegalEntityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Legal Entity [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after one to five years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reconciliation of Revenue from Segments to Consolidated [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Changes in assets and liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesPastDue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">As a percentage of total loans, Total Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesPastDue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loans And Leases Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesPastDue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loans and leases past due.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Outstanding, beginning of period, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Options outstanding, end of period, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after one to five years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Repossessed Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repossessed assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring and Nonrecurring [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OmnibusIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Omnibus Incentive Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OmnibusIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Omnibus Incentive Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OmnibusIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The omnibus incentive plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial Mortgage Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial Mortgage-Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Average rate paid during the period, including amortization of debt issuance costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Long term debt average rate paid including amortization of debt issuance costs.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt Average Rate Paid Including Amortization Of Debt Issuance Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturity after five to ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Frequency</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Insurance expense and assessments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Insurance expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">General Insurance Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Income Location, Balance [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectSalesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indirect Sales [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectSalesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indirect Sales [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectSalesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents indirect sales of consumer loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing within one year, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditQualityInformationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Quality Information [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Mortgage loans in process of foreclosure, amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Mortgage Loans in Process of Foreclosure, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Unrealized holding gains arising during the period on effective cash flow hedge derivatives, tax benefit (expense)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding gains (losses) arising during the period on effective cash flow hedge derivatives, net of tax expense (benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for Credit Losses on Loans and Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from financing activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FixedAssetValuationAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fixed asset valuation adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FixedAssetValuationAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fixed Asset Valuation Adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FixedAssetValuationAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fixed asset valuation adjustments.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Recurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total future minimum lease payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to Fixed Rate Commercial Real Estate Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To Fixed Rate Commercial Real Estate Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to fixed rate commercial real estate loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">ASC 326 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of Adopting CECL [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update 2016-13 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cumulative basis adjustments associated with hedging relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cumulative Basis Adjustments Associated With Hedging Relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Cumulative basis adjustments associated with hedging relationships.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Less: Imputed interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, Undiscounted Excess Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablePortfolioSegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing Receivable Portfolio Segment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablePortfolioSegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable Portfolio Segment [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DescriptionOfMaturityPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Description of maturity period.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DescriptionOfMaturityPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Description of Maturity Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DescriptionOfMaturityPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturities description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Asset Impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Goodwill and Intangible Asset Impairment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and other intangible assets write down</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest and Dividend Income, Securities, Operating, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on investment securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Securities, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank, advances, general debt obligations, disclosures, collateral pledged</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Components [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Component</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Component [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Performing Financial Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performing And Non Performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Performing And Non Performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Performing And Non Performing [Member].</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other-than-temporary impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other-than-temporary Impairment Loss, Debt Securities, Held-to-Maturity, Recognized in Earnings, before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets interest rate floors.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets Interest Rate Floors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Noninterest Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeExpenseNetMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Interest Income (Expense) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeExpenseNetMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense) Net [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeExpenseNetMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest income (expense) net.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash surrender value of bank-owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Bank Owned Life Insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Business Acquisition</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after five to ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Lease Income, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherInterestAndDividendIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Interest and Dividend Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherInterestAndDividendIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral exposure with FHLB in form of advances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advance, Branch of FHLBank, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SoftwareMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Software [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SoftwareMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Software [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SoftwareMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Software.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossGains_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossGains_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Gross Gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossGains_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate gross gains.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans pledged as collateral</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Financing Receivable, after Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Comprehensive Income [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Liabilities, Fair Value Disclosure, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial and Nonfinancial Liabilities, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives Designated as Hedging Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Designated as Hedging Instrument [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net loans and leases held for investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total loans, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Net Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total loans held for investment, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Exercised, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Value, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value $0.01 per share, 10,000,000 shares authorized; 8,019,126 and 7,947,303 shares issued, respectively; 5,523,209 and 5,699,696 shares outstanding, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Funds Purchased</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Purchased</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Decrease to retained earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total shareholders&#8217; equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance, value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance, value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity, Including Portion Attributable to Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bank-owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Bank Owned Life Insurance Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Increase in cash surrender value of bank owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ComputerServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Computer services</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ComputerServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Computer Services Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ComputerServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Computer services expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeATMFees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ATM fee income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeATMFees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income A T M Fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeATMFees_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other income ATM fees.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, off-Balance-Sheet Risks, Disclosure Information [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite-Lived Intangible Assets by Major Class</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansHeldForInvestmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans held for investment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansHeldForInvestmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans held for investment.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansHeldForInvestmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LHFI [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net1</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income (expense)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net share-based compensation transactions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net share-based compensation transactions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payment, Tax Withholding, Share-Based Payment Arrangement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Notional Amount and Fair Value of Derivative Instruments Included on Company's Consolidated Balance Sheets on a net Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Derivative Instruments In Statement Of Financial Position Nominal Amount And Fair Value Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tabular disclosure of the location, nominal amount and fair value amounts of derivative instruments (and non-derivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest-Bearing Deposit Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest-bearing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest-Bearing Deposit Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsNotesAndLoansReceivableLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts, Notes, Loans and Financing Receivable [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-sale, gross unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresDescriptionOfCollateralPledged_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral Requirements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresDescriptionOfCollateralPledged_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Description of Collateral Pledged</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorDeferredShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average director deferred shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorDeferredShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted average director deferred shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorDeferredShares_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average director deferred shares.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Increase (decrease) in cash surrender value of bank owned life insurance.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (decrease) in cash surrender value of bank owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Increase in cash surrender value of bank owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateCapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets interest rate caps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateCapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets Interest Rate Caps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">SOFR [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income Tax Expense (Benefit), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Frequency</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share Based Compensation Arrangement By Share Based Payment Award [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available lines of credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share based compensation arrangement by share based payment award equity instruments other than options released from restriction in period weighted average grant date fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share-based compensation arrangement by share-based payment award equity instruments other than options released from restriction in period weighted average grant date fair value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Released from restriction, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Common Stock, Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Common Stock, Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Derivative Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase in fair value of derivatives not designated as hedging instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Financing receivable, allowance for credit loss, writeoff, after recovery table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">US States and Political Subdivisions Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US States and Political Subdivisions Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByLiabilityClassAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liability Class [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated other comprehensive loss, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accumulated Other Comprehensive Income (Loss), Net of Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income (Loss), Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidationItemsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidation Items [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Charge-offs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, Allowance for Credit Loss, Writeoff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments to Acquire Property, Plant, and Equipment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of premises and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fixed asset additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to Acquire Property, Plant, and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Granted (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositLiabilitiesAccruedInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositLiabilitiesAccruedInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposit Liabilities, Accrued Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performing Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Performing Financial Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Financing Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Financing Receivable [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Past Due [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAmountOfHedgedItem_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Designated hedged items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAmountOfHedgedItem_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Amount of Hedged Item</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Restructuring And Related Costs [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Cost [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateCapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Cap [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Securities Heldtomaturity Allowance For Credit Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Income Tax Expense (Benefit), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred income tax provision</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Deferred income tax expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_WeightedAverageMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted Average [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_WeightedAverageMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Foreclosed Property Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Assets Acquired In Foreclosure Roll Forward Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate assets acquired in foreclosure roll forward.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Net increase decrease to income before income taxes.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Increase (Decrease) to Income Before Income Taxes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net (decrease) increase to income before income taxes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Earnings Per Share, Diluted, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Diluted net income per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnamortizedPremiums_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans net of unamortized premiums</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnamortizedPremiums_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans net of unamortized premiums.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnamortizedPremiums_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans net of unamortized premiums</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-accruing loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Segment Reporting Information, by Segment [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Information Related To The Company's Bank Operating Segment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingSegmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Segments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingSegmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Segments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PPPLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">PPP Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PPPLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">P P P Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PPPLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">PPP loans member</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title and Position [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Dividends, Common Stock, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Dividends declared</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Dividends, Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnShortTermBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on Short-Term Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnShortTermBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest On Short Term Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnShortTermBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest on short-term borrowings member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">City Area Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageNumberOfSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average shares outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageNumberOfSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageNumberOfSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average number of shares outstanding.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other comprehensive (loss) income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLossesExpensed_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Credit Loss, Expense (Reversal)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLossesExpensed_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for (recovery of) credit losses on loans and leases/unfunded lending commitments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StandbyPerformanceLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Standby Performance Letters of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StandbyPerformanceLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Standby Performance Letters Of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StandbyPerformanceLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to standby performance letters of credit.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Deposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Deposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromLoansReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments for (Proceeds from) Loans Receivable, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromLoansReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for (Proceeds from) Loans Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromLoansReceivable_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net (increase) in loans and leases held for investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Principal amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Face Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Goodwill and Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Intangible Assets and Goodwill [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AdditionalIncreaseToAllowanceForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional increase to allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AdditionalIncreaseToAllowanceForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Additional increase to allowance for loan and lease losses.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AdditionalIncreaseToAllowanceForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional increase to allowance for credit losses on loans and leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherRealEstateAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Losses Write Offs Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs current fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2026</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Federal Home Loan Bank, Advance, Maturity, Year One, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advance, Maturity, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest and Fee Income, Loans and Leases, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest and fees on loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Fee Income, Loans and Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralWithRightMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Pledged as Collateral with Right [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateFloorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Floor [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateFloorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floor [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessExitCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease termination costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessExitCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Exit Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwaps_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities - customer-related interest rate swaps</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwaps_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other liabilities customer related interest rate swaps</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwaps_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities - customer-related interest rate swaps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average remaining lease term (in years)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Weighted Average Remaining Lease Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Lease, Cost, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease, Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateFloorContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of interest rate floor contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateFloorContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Interest Rate Floor Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateFloorContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of interest rate floor contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and equipment, net of accumulated depreciation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property, Plant and Equipment, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and leases, allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for credit losses on loans and leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Less: allowance for credit losses on loans and leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2009/role/netLabel">Less: Allowance for credit losses on loans and leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Multifamily Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by multi-family residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by Multi family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retained Earnings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Share-Based Payment Arrangement, Noncash Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Noncash Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSold_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSold_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for credit losses, held-to-maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable Allowance, Held-to-Maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans and leases receivable allowance, held-to-maturity.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Insured or Guaranteed by Government Authorities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans Insured or Guaranteed by Government Authorities [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, less than 12 months, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average discount rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Weighted Average Discount Rate, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments for (Proceeds from) Federal Home Loan Bank Stock, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for (Proceeds from) Federal Home Loan Bank Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net increase in Federal Home Loan Bank stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities - credit risk participation agreement member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities - Credit Risk Participation Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Liabilities - Credit Risk Participation Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash (used in) provided by financing activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollateralDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Held [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short Term Debt [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCostTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease, Cost [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCostTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Components of Lease Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2023</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after five to ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsUnderManagementCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Carrying Amount of the Hedged Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsUnderManagementCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets under Management, Carrying Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeContractTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeContractTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Contract [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Interactive Data Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Interactive Data Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Income Location, Balance [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Measurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurement [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Securities Held To Maturity Allowance For Credit Loss [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan Restructuring Modification</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loan Restructuring Modification [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReissuanceOfTreasuryStockAsCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reissuance of treasury stock as compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReissuanceOfTreasuryStockAsCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reissuance of Treasury Stock As Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReissuanceOfTreasuryStockAsCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Reissuance of treasury stock as compensation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingRevenueReconcilingItemLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Revenue Reconciling Item [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, Operating Lease, Period of Option to Terminate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Period Of Option To Terminate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The period of time in which the lessee holds the option to terminate an operating lease, in 'PnYnMnDTnHnMnS' format. For example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FirstUnitedSecurityBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">FUSB [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FirstUnitedSecurityBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">First United Security Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FirstUnitedSecurityBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents a business segment of the company.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Dividends, Per Share, Declared</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_CumulativeEffectPeriodOfAdoptionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cumulative Effect, Period of Adoption [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Communications and Information Technology, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Telephone/data communication</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Communications and Information Technology</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Tax Identification Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Tax Identification Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Debt, Type</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from maturities and prepayments of investment securities, available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OccupancyNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net occupancy and equipment</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans, Notes, Trade and Other Receivables Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LocalPhoneNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Local Phone Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LocalPhoneNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Local Phone Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Deferred Compensation Arrangement With Individual Share Based Payments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement with Individual, Share-Based Payment [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">OREO and other assets held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Other Assets Measurement Input</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate other assets measurement input.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NotRatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Not Rated [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NotRatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Not rated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total non-interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total non-interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Financing Receivable Recorded Investment Credit Quality Indicator [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Credit Quality Indicator [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAverageCapInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Average Cap Interest Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAverageCapInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest rate cap, strike rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Four</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2030</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LaborAndRelatedExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Salaries and employee benefits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LaborAndRelatedExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Labor and Related Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SelfInsuranceReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Self Insurance Reserve</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SelfInsuranceReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Self Insurance Reserve</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Emerging Growth Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Emerging Growth Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding, weighted average remaining contractual term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">FHLB Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">FHLB Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefInformationAndConsumerBankingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief information and consumer banking officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefConsumerLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief consumer lending officer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefCommercialLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief commercial lending officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefInformationAndConsumerBankingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief information and consumer banking officer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefConsumerLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief consumer lending officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefRiskOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief risk officer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefRiskOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief risk officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefCommercialLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief commercial lending officer.</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:to="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="fusb_InterestIncomeRecorded" xlink:to="fusb_InterestIncomeRecorded_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_SegmentDomain_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear" xlink:to="us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityIncorporationStateCountryCode" xlink:to="dei_EntityIncorporationStateCountryCode_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_BalanceSheetLocationDomain_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivablePortfolioSegmentAxis" xlink:to="us-gaap_FinancingReceivablePortfolioSegmentAxis_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts" xlink:to="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCurrentReportingStatus" xlink:to="dei_EntityCurrentReportingStatus_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel2Member" xlink:to="us-gaap_FairValueInputsLevel2Member_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="fusb_InterestRateFloorContractsTwoMember" xlink:to="fusb_InterestRateFloorContractsTwoMember_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashFlowHedgingMember" xlink:to="us-gaap_CashFlowHedgingMember_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesAuthorized" xlink:to="us-gaap_CommonStockSharesAuthorized_lbl"/>
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        <link:definitionLink xlink:type="extended" xlink:role="http://www.firstusbank.com/20260630/taxonomy/role/DisclosureLoansAndLeasesScheduleOfAmortizedCostBasisOfCollateralDependentLoansDetails">
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          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfessionalFees" xlink:label="us-gaap_ProfessionalFees"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SuppliesAndPostageExpense" xlink:label="us-gaap_SuppliesAndPostageExpense"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommunicationsAndInformationTechnology" xlink:label="us-gaap_CommunicationsAndInformationTechnology"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20260630.xsd#fusb_CollectionAndRecoveries" xlink:label="fusb_CollectionAndRecoveries"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoninterestExpenseDirectorsFees" xlink:label="us-gaap_NoninterestExpenseDirectorsFees"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="us-gaap_AmortizationOfIntangibleAssets"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20260630.xsd#fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingOtherItemAmount" xlink:label="us-gaap_SegmentReportingOtherItemAmount"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit"/>
        </link:calculationLink>
      </link:linkbase>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwaps" name="OtherLiabilitiesCustomerRelatedInterestRateSwaps" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_CommercialAndIndustrialLoansAndLeasesMember" name="CommercialAndIndustrialLoansAndLeasesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm" name="LongTermDebtWeightedAverageRemainingMaturityTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" name="OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsOneMember" name="ForwardInterestRateSwapContractsOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NotRatedMember" name="NotRatedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InvestmentIntoCapitalSurplus" name="InvestmentIntoCapitalSurplus" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity" name="LoansAndLeasesReceivableAllowanceHeldToMaturity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_InterestRateFloorContractsOneMember" name="InterestRateFloorContractsOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherMember" name="OtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_GoodwillAndOtherIntangibleAssetsLineItems" name="GoodwillAndOtherIntangibleAssetsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_InterestIncomeRecorded" name="InterestIncomeRecorded" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_DecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements" name="DecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember" name="InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherAssetsCustomerRelatedInterestRateSwapsMember" name="OtherAssetsCustomerRelatedInterestRateSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation" name="ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CommitmentsToExtendCredit1Member" name="CommitmentsToExtendCredit1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ReissuanceOfTreasuryStockAsCompensation" name="ReissuanceOfTreasuryStockAsCompensation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_SoftwareMember" name="SoftwareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_IndirectSalesMember" name="IndirectSalesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember" name="InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock" name="OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit" name="FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts" name="LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax" name="OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_IndirectConsumersMember" name="IndirectConsumersMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_PercentageOfLoansAndLeases" name="PercentageOfLoansAndLeases" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_LoansHeldForInvestmentMember" name="LoansHeldForInvestmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CollateralDependentLoansFairValueDisclosure" name="CollateralDependentLoansFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_Customer-RelatedInterestRateSwapsMember" name="Customer-RelatedInterestRateSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_WeightedAverageDirectorDeferredShares" name="WeightedAverageDirectorDeferredShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_PerformingAndNonPerformingMember" name="PerformingAndNonPerformingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_IndirectMember" name="IndirectMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion" name="CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_FiveYearTermLoanMember" name="FiveYearTermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember" name="NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets" name="GainOnSalesOfPremisesAndEquipmentAndOtherAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_SecuredByNonResidentialCommercialRealEstateMember" name="SecuredByNonResidentialCommercialRealEstateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_GoodwillAndOtherIntangibleAssetTable" name="GoodwillAndOtherIntangibleAssetTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_PassAndCriticizedMember" name="PassAndCriticizedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember" name="RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_DerivativeInstrumentInterestRateIncreaseDecrease" name="DerivativeInstrumentInterestRateIncreaseDecrease" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ImpairedLoansFairValue" name="ImpairedLoansFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CorrespondentBanksMember" name="CorrespondentBanksMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts" name="LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CreditDerivativesMember" name="CreditDerivativesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommercialAndIndustrialLoansMember" name="CommercialAndIndustrialLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember" name="SecuredByRealEstate1To4FamilyResidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock" name="ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OmnibusIncentivePlanMember" name="OmnibusIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember" name="InterestRateSwapsRelatedToFHLBAdvancesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NetGainOnSalesAndPrepaymentsOfInvestmentSecurities" name="NetGainOnSalesAndPrepaymentsOfInvestmentSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_TerminationOfTechnologyContracts" name="TerminationOfTechnologyContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_PaycheckProtectionProgramMember" name="PaycheckProtectionProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_DirectConsumerMember" name="DirectConsumerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_PercentageOfLoanPortfolio" name="PercentageOfLoanPortfolio" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherAssetsInterestRateCapsMember" name="OtherAssetsInterestRateCapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_Customer-RelatedInterestRateSwapsOneMember" name="Customer-RelatedInterestRateSwapsOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FirstUnitedSecurityBankMember" name="FirstUnitedSecurityBankMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NetDeferredTaxAssetsLiabilitiesIncreaseDecrease" name="NetDeferredTaxAssetsLiabilitiesIncreaseDecrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate" name="LesseeOperatingLeasePeriodOfOptionToTerminate" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_MinimumCommitmentRequiredForEvaluatingIdividually" name="MinimumCommitmentRequiredForEvaluatingIdividually" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_NonEmployeeDirectorsMember" name="NonEmployeeDirectorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_StandbyPerformanceLettersOfCreditMember" name="StandbyPerformanceLettersOfCreditMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure" name="FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale" name="ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_BranchRetailMember" name="BranchRetailMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherIncomeAndExpensesTable" name="OtherIncomeAndExpensesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_IncomeTaxDisclosureLineItems" name="IncomeTaxDisclosureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1" name="DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ProceedsFromSettlementOfDerivativeContracts" name="ProceedsFromSettlementOfDerivativeContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable" name="OrganizationConsolidationAndPresentationOfFinancialStatementsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherNonInterestExpenseMember" name="OtherNonInterestExpenseMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateGrossLosses" name="OtherRealEstateGrossLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis" name="CollateralLoansIndividuallyEvaluatedAmortizedCostBasis" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CollateralDependentLoansMeasurementInput" name="CollateralDependentLoansMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherRealEstateNetIncomeLoss" name="OtherRealEstateNetIncomeLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherRealEstateOtherAssetsFairValueDisclosure" name="OtherRealEstateOtherAssetsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_PercentageOfLoansAndLeasesPastDue" name="PercentageOfLoansAndLeasesPastDue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsThreeMember" name="ForwardInterestRateSwapContractsThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember" name="OtherLiabilitiesCreditRiskParticipationAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToVariableRateMoneyMarketDepositAccountsMember" name="InterestRateSwapsRelatedToVariableRateMoneyMarketDepositAccountsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateCapOneMember" name="InterestRateCapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_IncomeTaxDisclosureTable" name="IncomeTaxDisclosureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfForwardStartingContractsTerminated" name="NumberOfForwardStartingContractsTerminated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_LoansNetOfUnamortizedPremiums" name="LoansNetOfUnamortizedPremiums" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_NumberOfInterestRateSwapContracts" name="NumberOfInterestRateSwapContracts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_CreditLossesOnUnfundedLendingCommitmentsMember" name="CreditLossesOnUnfundedLendingCommitmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ThePeoplesBankMember" name="ThePeoplesBankMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapOneMember" name="InterestRateSwapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ForeclosedAssetsAcquiredInSettlementOfLoans" name="ForeclosedAssetsAcquiredInSettlementOfLoans" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_NumberOfStates" name="NumberOfStates" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OtherIncomeATMFees" name="OtherIncomeATMFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_InterestIncomeExpenseNetMember" name="InterestIncomeExpenseNetMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock" name="ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherLiabilitiesCreditRiskParticipationAgreement" name="OtherLiabilitiesCreditRiskParticipationAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_TwoYearTermLoanMember" name="TwoYearTermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredByNonfarmNonresidentialPropertiesMember" name="SecuredByNonfarmNonresidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships" name="AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock" name="ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesGainLossRealizedInNetIncomeNetOfTax" name="OtherComprehensiveIncomeLossAvailableForSaleSecuritiesGainLossRealizedInNetIncomeNetOfTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_WeightedAverageDirectorStockEquivalentShares" name="WeightedAverageDirectorStockEquivalentShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_MaturityPeriodOfFederalFunds" name="MaturityPeriodOfFederalFunds" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ChiefInformationAndConsumerBankingOfficerMember" name="ChiefInformationAndConsumerBankingOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts" name="ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock" name="ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestOnDepositsMember" name="InterestOnDepositsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherNonInterestIncomeMember" name="OtherNonInterestIncomeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_TransitionAdjustmentIncreaseInLoanLossReserves" name="TransitionAdjustmentIncreaseInLoanLossReserves" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CreditRiskParticipationAgreementsMember" name="CreditRiskParticipationAgreementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_WeightedAverageNumberOfSharesOutstanding" name="WeightedAverageNumberOfSharesOutstanding" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AcceptanceLoanCompanyMember" name="AcceptanceLoanCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapTwoMember" name="InterestRateSwapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateFloorsMember" name="InterestRateFloorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ProceedsFromSaleOfPremisesAndEquipmentOtherRealEstateAndRepossessions" name="ProceedsFromSaleOfPremisesAndEquipmentOtherRealEstateAndRepossessions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms" name="DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsMember" name="ForwardInterestRateSwapContractsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredBy1To4FamilyResidentialPropertiesMember" name="SecuredBy1To4FamilyResidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CarryingAmountOfLoansByCreditQualityIndicatorAndYearOfOriginationTableTextBlock" name="CarryingAmountOfLoansByCreditQualityIndicatorAndYearOfOriginationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_NumberOfInterestRateSwapContractsTerminated" name="NumberOfInterestRateSwapContractsTerminated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_FederalFundsSoldFairValueDisclosure" name="FederalFundsSoldFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_NumberOfCreditRiskParticipationAgreement" name="NumberOfCreditRiskParticipationAgreement" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestOnShortTermBorrowingsMember" name="InterestOnShortTermBorrowingsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ChiefCommercialLendingOfficerMember" name="ChiefCommercialLendingOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ComputerServicesExpense" name="ComputerServicesExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_LongTermDebtMaximumMonthEndOutstandingAmount" name="LongTermDebtMaximumMonthEndOutstandingAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_PercentageOfLoansAndLeasesCurrent" name="PercentageOfLoansAndLeasesCurrent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_PercentageParValueAllowedAsCollateral" name="PercentageParValueAllowedAsCollateral" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsMember" name="OtherLiabilitiesCustomerRelatedInterestRateSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ChiefRiskOfficerMember" name="ChiefRiskOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships" name="CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ChiefConsumerLendingOfficerMember" name="ChiefConsumerLendingOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember" name="ConstructionLandDevelopmentAndOtherLandLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateOtherAssetsMeasurementInput" name="OtherRealEstateOtherAssetsMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AdditionalIncreaseToAllowanceForLoanAndLeaseLosses" name="AdditionalIncreaseToAllowanceForLoanAndLeaseLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestRateSwapThreeMember" name="InterestRateSwapThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_EmployeesMember" name="EmployeesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateCapTwoMember" name="InterestRateCapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember" name="InterestRateSwapsRelatedToInterestBearingLiabilitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_RealEstate1Member" name="RealEstate1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock" name="ScheduleOfOtherOperatingIncomeByComponentTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestRateFloorContractsTwoMember" name="InterestRateFloorContractsTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredByMultifamilyResidentialPropertiesMember" name="SecuredByMultifamilyResidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_DescriptionOfMaturityPeriod" name="DescriptionOfMaturityPeriod" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_FixedAssetValuationAdjustments" name="FixedAssetValuationAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsTwoMember" name="ForwardInterestRateSwapContractsTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherAssetsInterestRateFloorsMember" name="OtherAssetsInterestRateFloorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_EquipmentFinancingLeasesMember" name="EquipmentFinancingLeasesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestOnBorrowingsMember" name="InterestOnBorrowingsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed" name="RestructuringAndRelatedCostNumberOfOfficeClosed" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestAndFeesOnLoansMember" name="InterestAndFeesOnLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale" name="GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_NumberOfInterestRateFloorContracts" name="NumberOfInterestRateFloorContracts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock" name="ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance" name="IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_PPPLoansMember" name="PPPLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives" name="RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OtherRealEstateGrossGains" name="OtherRealEstateGrossGains" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts" name="ForeclosedRealEstateOwnedFairValueLessDisposalCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_LesseeOperatingLeaseRemainingTermOfContract" name="LesseeOperatingLeaseRemainingTermOfContract" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_CollectionAndRecoveries" name="CollectionAndRecoveries" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OtherIncomeAndExpensesLineItems" name="OtherIncomeAndExpensesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
