Tweak FAT detection/usage. Recognize 'bare' FAT media that lacks the 0x55aa signature. Don't try FAT detection if we have found an OpenBSD MBR partition. Don't try to read a disklabel from 'bare' FAT media. There can't be one.
Tweak FAT detection/usage. Recognize 'bare' FAT media that lacks
the 0x55aa signature. Don't try FAT detection if we have found an
OpenBSD MBR partition. Don't try to read a disklabel from 'bare'
FAT media. There can't be one.

Finally, don't allow the writing of a disklabel on 'bare' FAT media.
There is no safe spot for it, and splatting it in the middle of the
FAT structures has not proved helpful.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars