The most common issue with using littlefs in mbed-os is when users
change from littlefs->FAT->littlefs (or with MBR or similar). When this
corrupts the superblock, littlefs tries to fall back to the backup
superblock. However, at this point in the time the old superblock may be
very out-of-date and pointing to an incorrect filesystem.
There's no complete solution to a malicious modification of the
filesystem (short of checking all metadata+data, a very expensive
operation), but we can at least expand our validation to all of the
metadata for the filesystem. This at least catches the common issues
with changing between different filesystems.
CRC used in LittleFS is Reversed ANSI, hence new polynomial added.
Reversed polynomials perform shift in reverse direction of standard
polynomial, and we do not have option to notify reverse shift to hardware.
Hence this option is available in software only.