TurboTax has been recently updated to reflect both payments. If you are not seeing the option to provide both amounts in Federal Review please update your software, if using Desktop software.
If you are an online TurboTax user, your software should update automatically. However, it may be necessary to log out of TurboTax, clear your browser cache & cookies, and log back in to ensure you are seeing the most up-to-date version of the program.
You will claim the Recovery Rebate Credit in TurboTax by answering the two questions about the stimulus payments that will appear at the end of the TurboTax interview.
The questions are in the section Federal Review.
Once the information is entered you will see your refund increase or balance due decrease, and TurboTax will enter the amount of the credit on Line 30 of Form 1040 for you.
CAUTION: Please wait until after January 15th to submit a return with $0 entered for the second payment as the IRS is still processing many payments. It will not delay your refund as the IRS is not expected to begin processing tax returns before this date.