Report the first stimulus check on your tax return and put $0 for the second payment. IRS records will show the government sent the first stimulus check so the amount will be deducted from your refund if you try and claim it a second time as a Rebate Recovery Credit.
That will delay for refund.
The check is expired. Is there any way I can get my 1st stimulus check ?
If you received your payment by check and it was lost, stolen or destroyed, you may need to request a payment trace so the IRS can determine if your payment was cashed. See How do I request a payment trace to track my first or second Economic Impact Payments?
If a trace is initiated and the IRS determines that the check wasn’t cashed, the IRS will credit your account for that payment, but the IRS cannot reissue your payment. Instead, you will need to claim the 2020 Recovery Rebate Credit on your 2020 tax return if eligible.
You will enter $0 for both stimulus payments. Please be aware that the processing of our return will be longer since the IRS will have to match the information.