HP LaserJet 1020 "Device Busy"

[Modulok]

If anyone out there has this printer or knows anything about printing
in general...

My printer: HP LaserJet 1020
www.linuxprinting.org recommended driver: foo2zjs

1. I install the port  /usr/ports/print/foo2zjs.
2. I plug the printer into the USB port, dmesg reports:
	
ulpt0: Hewlett-Packard HP LaserJet 1020, rev 2.00/1.00, addr 2, iclass 7/1
ulpt0: using bi-directional mode
	
3. The foo2zjs docs state the printer needs to have its firmware
uploaded first: # cat ./sihp1020.dl > /dev/ulpt0
	
After several minutes (5, maybe 10) I get: "/dev/ulpt0: Device busy."

Where did I go wrong?
-Modulok-