Darren's right the TiVo doesn't have anyway of mapping bad sectors, and Zolly's method is pretty safe if the bad sectors are only in the MFS and not the file system.

We do however have a couple of tools for checking for errors on the TiVo without removing the drive.

mfscheck and fsfix. Both of these will check the drive, mfscheck will only check the recordings area and fsfix will check the system file area.

FYI, when running either of these your TiVo will freeze and stop recording shows. Reboot between each test.

Peter.