Recently my Sansa Clip+ died on me randomly. I had Rockbox installed for about two years and then one day when I booted it up it just said "File not found". Makes sense, flash can be temperamental. In anycase, for any of yall in the same position, here's the quick restore procedure to get your Rockbox root fs back and booting:
Plug in your Clip+ and wipe the partition table, make a new partition, format it vfat, and mount it:
fdisk /dev/sdb (your device) --> proceed to delete (d) any existing partitions, (in my case there were none) --> make a new partition (n), set filesystem type(t) to b --> write (w) out mkfs.vfat /dev/sdb1 (your device partition) mkdir /mnt/clip mount /dev/sdb1 /mnt/clip
Now you've got a partition to work with, so proceed with normal Rockbox setup procedure. Download the Rockbox firmware and copy it over to your clip:
wget http://build.rockbox.org/data/rockbox-sansaclipplus.zip unzip rockbox-sansaclipplus.zip mv .rockbox /mnt/clip
Then, patch and copy over the bootloader the manual way (GUI didn't work for me):
wget http://mp3support.sandisk.com/firmware/clipplus/clipplus01.02.16.zip wget http://download.rockbox.org/bootloader/sandisk-sansa/clipplus/bootloader-clipplus.sansa wget http://download.rockbox.org/bootloader/sandisk-sansa/mkamsboot/linux-x86-32/mkamsboot unzip clipplus01.02.16.zip ./mkamsboot clppa.boot bootloader-clipplus.sansa patched.bin cp patched.bin /mnt/clip/clppa.bin umount /mnt/clip
Unplug the Clip+ and Rockbox should be working again.