Hi,

>>># fsck_msdos /dev/wd0f
>>>** /dev/wd0f
>>>backup doesn't compare to primary bootblock

The FAT filesystem has some information vaguely similar to the
superblock in the very first block of the partition (traditionally
called the bootblock with DOS).  With VFAT32, a copy of this
information was introduced that is some blocks into the partition
(normally block 6 IIRC).

Since there isn't much checking of the plausibility of the
information found here, fsck_msdos in its current version chokes
if these blocks don't compare, on the assumption that the
filesystem probably isn't a FAT filesystem at all, but
something else (which is most likely the cause of your
problem, too).

Try looking at a dump of the beginning of the partition to
determine whether this is really a FAT filesystem.

> This is the character device.  Anyway, same diff with rwd0f.

Seems that you've got it backwards here (except if you have
some rather weird names in your /dev directory ;-)).
Normally, /dev/wd0f is the block device and /dev/rwd0f is
the raw, aka character device, as can be determined from the
first column of an "ls -l /dev/*wd0f".

Ciao,
Wolfgang
-- 
ws@TooLs.DE	Wolfgang Solfrank, TooLs GmbH	+49-228-985800