Emmc mount fail

The superblock is corrupt. That’s kind of a master listing of content (notes). That’s pretty bad, and you probably can’t save it (if you can, it will be pieces, and the process best performed on a Linux PC with plenty of disk space).

It could be hardware failure, but that’s unlikely. Things like improper shutdown (including power loss) would typically cause something like this. I don’t see this as “disk full”, I see this as “the data is so corrupt it isn’t known how to fix it”. Has this unit been shut down with proper software commands?

Incidentally, here is some background: