thanks zerozero - it worked like a charm!
By the way, after it finished:
Greg-LinuxMint greg # xzcat FreeNAS-8.3.0-RELEASE-p1-x64.img.xz | dd of=/dev/sdb1 bs=64k
552+238777 records in
552+238777 records out
2000000000 bytes (2.0 GB) copied, 378.382 s, 5.3 MB/s
Greg-LinuxMint greg # and I went to close terminal i got this message:
There is still a process running in this terminal. Closing the terminal will kill it.
What the heck would that have been? Any idea?
All I did was su to root, ran blkid to make sure I had the correct device, burn the image to the usb and close termainal. Nothing else.