You can only use the rmformat command to verify, analyze, and repair bad sectors that are found during verification if the drive supports bad block management. Most USB memory sticks do not support bad block management.
If the drive supports bad block management, a best effort is made to rectify the bad block. If the bad block cannot be rectified despite the best effort mechanism, a message indicates the failure to repair the media.
$ rmformat -c block-numbers device-name
Supply the block number in decimal, octal, or hexadecimal format from a previous rmformat session.
$ rmformat -V read device-name