Did this ever get resolved? I'm having the same problem, and I _think_ I may know (part of) the problem. The error message talks about "/dev/ad0s1b" however in the Fixit shell a listing of /dev/ad* gives things like /dev/ad0a /dev/ad0b /dev/ad0c /dev/ad0d etc.. This happens whether I use slices or choose "dd" mode. Robert Huff