DELL R200 afd0?/geom panic

I'm running current (from beta-1 to head) in this system and looks like the 
virtual floppy support is breaking geom somehow.

Sometimes the system boots fine, but normally after a reboot the system 
refuses to boot again with this panic:

(a few more errors from afd0)
afd0: FAILURE - READ_CAPACITY_RESERVED asc=0x0d ascq=0xbf
afd0: FAILURE - TEST_UNIT_READY ABORTED COMMAND asc=0x09 ascq=0x3f
panic: g_read_data(): invalid length 4174017282

(hand transcribed again...)

The length isn't fixed (i see a different value every time).

Does anyone knows how to disable the support for this device (afd0) ? I 
don't care about it...

I'll appreciated any suggestions.

Thanks,
Luiz