Mine was a bit more FUBAR I guess. I have a Sansa e260. I had rockbox on it, went to switch back to the firmware. Uninstalled rockbox and on reboot... the e260 was refreshing the database and then came to a frozen green screen.
My e260 was already in MSC mode. I did the steps above but was still stuck.
The solution that worked was one posted by "Slaughter" on anythingbutipod.
The ultimate fix for all e2xx v1 problems - Format, enter recovery mode
, downgrade firmware Link
(you'll need to format the drive), reinstall newest firmware via newest Sansa Updater
, reload tunes.