Well, it worked here for me (I even downloaded the morphos2.0.iso to the same stick and installed from there).

Make sure your stick contains a partition. Dont know how to explain this, but e.g. in linux a stick can appear as either /dev/sdx or /dev/sdx1. Both are valid, but scsi:0 looks for the later.

Does ls scsi:0 list the files in the stick?