Djen dobre Dawid,

judging out of my own experience with a IOmega mini Drive, you have one
major problem : your stick should be detected as SCSI over USB (Using
SCSI over bulk-only). At first, I'd got this message too, just because
the config file commented out "sd0 at umass ?". I am pretty sure the
driver cannot find the geometry, nor send the necessary sense commands
to the key, so that when you try to mount it, it hangs (something I
experienced too). 

Then I can't figure out why you have a second detection on a different
port with a generic driver ugen.  

Vincent