~ # fsck.fat /dev/lock/mmcblk1p1
fsck.fat 3.0.28 (2015-05-16)
0x41: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
1) Remove dirty bit
2) No action
? 1^H2
FATs differ but appear to be intact. Use which FAT ?
1) Use first FAT
2) Use second FAT
? 1
Reclaimed 7 unused clusters (229376 bytes).
Perform changes ? (y/n): y
/dev/block/mmcblk1p1: 310 files, 7718/973584 clusters