Disk Maintenance on HD-FOX

Black Hole

May contain traces of nut
There is no fix-disk option on the HD-FOX Telnet (maintenance mode) menu. Is this because the tools aren't there, or it's not technically viable to operate on a USB drive, or because it was not considered necessary when the drive can be moved elsewhere?

If the latter, can somebody suggest appropriate command-line hacks for disk maintenance, particularly for a drive that's gone read-only?