Questions about Wrong Total basis in Traditional IRA on form 8606 from previous year

Hi,

In year 2021, my 8606 Total Basis is $6,000.

In year 2022 and 2023, my Traditional IRA contribution were tax deductible (so no 8606 produced).

In year 2024, my Traditional IRA contribution is $7,000, but the 8606 Total Basis is $0 (it should be $6,000, from year 2021, somehow Turbotax didn't carryover the Total Basis from 2021). -- I didn't realize this mistake.

 

So two questions:

1) How should I correct the wrong Total Basis in 2024?

2) I am about to file my 2025 tax, should I put in the corrected Total Basis, i.e., $6,000 (from 2021) + $7,000 (from 2024) = $13,000 Total Basis?

 

Thank you for reading.