Wow.  The 9122 exceeded my expectations.

You can create boot floppies without any special hardware and without
running HP-UX.  Here's what I did:

Format a blank low density floppy as DOS 720 KB in a mac/pc/unix machine
dump SYS_UBOOT onto the floppy (with dd under unix, suntar on mac)
insert into 9122, and boot up the hp300 (this worked on a 340 and a 425s).

Cool!

Not only that, but it appears that NetBSD can access the left drive (I
couldn't get to the right floppy) of the 9122 as a /dev/rdX device!  I'm
not sure how useful this may be (I only was able to read the first 360 KB
of the disk), but it's nice to know. 

  -- MW