The Problem Machine is one of the Compaqs from about 1997/8 without a
"real"
BIOS.

BTW, it *does* have a BIOS

Well yes; I was trying to be brief, and "real" seemed better than "of
the kind we're familiar with from most other pc-clones".

and it *is* flashable. The bit that resides on that
weird partition is the configuration utility for it, not the BIOS itself. From
your description of it as a P-II, 233MHz I would guess that it's one of these
models -
http://h18007.www1.hp.com/support/fi...?lang=en&cc=us
and probably the 6233X or 6233MMX since a 5233MMX is a Pentium I not a II.

Ah! Thank you; I didn't know that. Maybe I needed a different setup
utility, though sp8126.exe seemed to claim very general applicability.
I spent a while at the Compaq site searching without success for a list
of the attributes of the models so as to identify which one I had.
Does anyone know what distinguishes the X from the MMX?

If you take the link from that page for the 6233X then you can choose MS-DOS as its
o/s on the next page and the first thing listed is a flash BIOS for it - you
want the 3rd link down which will create a boot diskette and flash your BIOS.

Having lost some functionality by acting without all the necessary
information (gasp!), and having had one possible fix inexplicably fail,
I'm reluctant to do something irreversible which could destroy the
remaining functionality if done less than perfectly. Remember, I don't
have a real MSDOS (although I had one in 1997 that's probably still in
my junk^H^H^H^Harchives), so thus far I've done all the DOS stuff in
dosemu or FreeDos, which risks subtle incompatibilities. That said,
thanks again, and I'll look into what's at the location you cited.

(Does any one know if Compaq incorporate extensive sanity/applicability
checks into their BIOS upgrade software, thus reducing the likelihood
of User Error being catastrophic?)

(Does anyone know a way to recover from a BIOS upgrade later determined
to be bad, other than taking the PROM/NVRAM off the motherboard and
using a special device to reprogram it?)