After the amended return was accepted and approved, the second Married Filing Separate return could be e-filed. However, the stimulus money would not be increased by filing separated when claiming the Recovery Rebate Credit.
While one spouse may be able to receive the whole amount, the other spouse's income would be reduced by $5 for each $100 above $75,000 for married, separate filers, not $150,000 for married, joint filers.
To calculate it yourself, see page 58 of 2020 Form 1040 Instructions for the Recovery Rebate Credit Worksheet.
For more information, see: Should You and Your Spouse File Taxes Jointly or Separately? - TurboTax Tax Tips & Videos
