I'm running a recent NetBSD/macppc 4.99.4 kernel (userland is somewhat
older).  I'm trying to use a HP Laserjet 1020 USB printer:

ulpt0 at uhub3 port 1 configuration 1 interface 0
ulpt0: Hewlett-Packard HP LaserJet 1020, rev 2.00/1.00, addr 2, iclass 7/1
ulpt0: using bi-directional mode

Following pointers on http://www.linuxprinting.org, I went to
http://foo2zjs.rkkda.com/ and installed foo2zjs.  It says that I have
to upload a firmware file to the printer, but

# cat /usr/share/foo2zjs/firmware/sihp1020.dl > /dev/ulpt0

seems to do nothing.  top says that the shell is in the "usbsyn"
state.  After a couple of minutes, it says "device busy".  Actually
trying to print anything meets the same fate.

Any ideas?

Magnus