my wife got me a creative labs muvo N200 for christmas, and it appears
to be supported by umass:  (when contiguous memory is available, but
that's another issue)

umass0 at uhub0 port 2 configuration 1 interface 0
umass0: CREATIVE MuVo N200, rev 2.00/0.01, addr 2
umass0: using SCSI over Bulk-Only
scsibus1 at umass0: 2 targets, 1 lun per target
sd0 at scsibus1 target 0 lun 0: <CREATIVE, MuVo N200, 0001> disk removable
sd0: fabricating a geometry
sd0: 496 MB, 496 cyl, 64 head, 32 sec, 512 bytes/sect x 1015808 sectors

however, mount_msdos refuses to mount the partition and doesn't give any
useful clues as to what the problem is:

# mount -t msdos /dev/sd0e /mnt
mount_msdos: /dev/sd0e on /mnt: Invalid argument

yet the same method works for floppy (replace sd0e with fd0a).

mtools can read and write the partition just fine, so what's the
kernel's problem?

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | agrier@poofygoof.com
    The United States is the one true country.  The US is just.  The US
    is fair.  The US respects its citizens.  The US loves you.  We have
    always been at war against terrorism.