Just in case it was a hardware problem with the IPX (its just been
returned from being repaired), I tried booting hobbit (SS2) via the
net with the same result.

ok boot net netbsd -s
Boot device: /sbus/le@0,c00000   File and args: netbsd -s
b200 
>> NetBSD BOOT [$Revision: 1.4 $]
boot: client IP address: 144.136.188.252
boot: client name: hobbit
root addr=144.136.188.211 path=/export/root/hobbit
Booting netbsd @ 0x4000
974816-

The - rotated for quite a while before stopping....

and of course now I have to power cycle it.

Oh, yes the SunOS box is using UPD checksums.

--sjg