Minimum volume size for fat12

I am searching for the answer, what is the theoretical minimum size for a FAT12 volume?

There is only requirements that embedded and normal systems should recognize it on a pen drive as legal file system. Small size as possible without filesystem driver crash. Even if only 1 data sector - that will be perfect! So what is the minimum legal size?

Thank You,

Solution 1:

mkfs.vfat, if you limit it to one FAT (-f 1) and 16 root directory entries (-r 16), still insists on a minimum of 33792 bytes (66 sectors × 512 bytes), although it uses only 10 sectors for the filesystem (56 sectors remain for data).

The filesystem remains mountable if you truncate it to 10 sectors, although attempting to write to such a truncated fs will result in the filesystem driver complaining.

You might have some luck with adjusting the filesystem structures with a hex editor, to properly shrink it to around 11 sectors...