Unsupported UFI command with Teac USB-Floppy

[sm4tnp8 at gmx.net]

Hi there!

I have a Teac USB-Floppy, but I'm not able to mount a disk. The device is
recognized as

umass0: TEAC     TEAC FD-05PUB   , rev 1.10/0.00, addr 2
da0 at umass-sim0 bus 0 target 0 lun 0
da0: <TEAC FD-05PUB 2000> Removable Direct Access SCSI-0 device
da0: 20KB/s transfers
da0: 1MB (2880 512 byte sectors: 2H 18S/T 80C)

To mount a disk (simple msdos formatted disk) I use:

sysctl kern.cam.da.no_6_byte=1
mount -t msdos /dev/da0c /mnt

which results in the following errors:

da0s1: slice starts beyond end of the disk: rejecting it
da0s2: slice starts beyond end of the disk: rejecting it
da0s3: slice starts beyond end of the disk: rejecting it
da0s4: slice starts beyond end of the disk: rejecting it
umass0: Unsupported UFI command 0x35
(da0:umass-sim0:0:0:0): Synchronize cache failed, status == 0x6, scsi status
== 0x0

Any ideas what is going / what am I doing wrong?