I installed Rockbox on my Sansa Clip+ (8GB if it makes a difference), and decided to remove it because of some organizational problems (Which seem petty now, considering my current situation).
I used the uninstaller, I deleted the .rocbox folder, I did what was recommended. The Clip+ wouldn’t boot up. I looked into it, and thought to put the manual firmware installation (clppa.bin) in the root folder, as recommended. No dice, it still wouldn’t work.
Finally, I gave up and formatted it (keeping it in FAT32, of course). I placed the clppa.bin in the root directory, all alone. . . and it wouldn’t work, leaving me where I am now.
Specifically, when I turn it on, the Rockbox logo comes up, above it it says something like “Finding Firmware File Not Found.” After that, the screen only says “File Not Found” and eventually switches to “Plug USB cable.” When I plug it in, it reads “Bootloader USB Mode” — I don’t know if that’s the Rockbox or the Sansa bootloader.