GEOM weirdness with SD flash reader?

Simply trying to mount a FAT filesystem in an external USB SD flash
reader.  The reader works fine, no errors in dmesg.

deenlo# fdisk da2
******* Working on device /dev/da2 *******
parameters extracted from in-core disklabel are:
cylinders=982 heads=64 sectors/track=32 (2048 blks/cyl)

parameters to be used for BIOS calculations are:
cylinders=982 heads=64 sectors/track=32 (2048 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 6 (0x06),(Primary 'big' DOS (>= 32MB))
    start 243, size 2011917 (982 Meg), flag 0
        beg: cyl 0/ head 3/ sector 55;
        end: cyl 998/ head 3/ sector 3
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>
deenlo# mount -t msdosfs /dev/da2s1 /mnt/dos
mount_msdosfs: /dev/da2s1: No such file or directory
deenlo# mount -t msdosfs /dev/da2 /mnt/dos
mount_msdosfs: /dev/da2: Invalid argument
deenlo# mount -t msdosfs /dev/da2s1 /mnt/dos
[success]

So I'm guessing GEOM had to decide to create /dev/da2s1 after I tried to
mount /dev/da2 directly?  Nothing else would create the da2s1 device.
Once the device was created with make_dev(), repeated unmounts/mounts
work fine.

-- 
Nate