I'd like to use the XT-IDE Universal BIOS with an IBM XT 286 (5162), but it's known to be incompatible. With the card installed, it will not boot from a floppy from which it would otherwise boot (it starts to, but then glitches out).
I plan to try third-party system BIOSes to see if that might fix it, but while I wait for EEPROMs to show up, I thought it might be worthwhile to see if I can fix whatever incompatibility there is directly. The source code seems unmaintained, though I did try flashing the latest version just in case (it has the same problem).
I'm a professional programmer by day with quite a lot of experience at low-level programming, but no experience with my new (to me) IBM or computers of its era. If I wanted to debug this problem, how might I start?