The upgrade completed, all went well… until I rebooted.
At this point, I discovered an unusual feature of the SiS 5513 controller under the new kernel — it gets scanned for SATA drives… & is broken. The IDE DVD drive works fine, but not the IDE hard drive.
I was able to swap this bog-slow 566MHz Celeron for a bog-slow 400MHz P2 (albeit with some dinking around with SD-RAM ’coz it only had 64MB & one DIMM socket is broken; & more dinking because the built-in LAN card wouldn’t work) built on an Intel chipset.
I did actually get a bonus, sort of, because it has built-in speakers. Hmmm. Starting to seriously exhaust the supply of random/spare computer parts to jam together for making things work.