Where to go from here surely is just buy an EEPROM programmer, they aren’t that expensive and are very handy to have around.

If the issue is just the EEPROM/Flash contents of the XT-IDE, you should still be able to boot from floppy with the EEPROM removed. After booting, reinstalling the EEPROM chip should allow another flash attempt. Practice hot-inserting the EEPROM without power applied until you feel confident that you won't cause a short before attempting this live, though.

There's a chance the EEPROM may have partially died. Certain parts of the memory can't be written anymore. I had this happen to me after flashing an EEPROM many times.

Getting an EEPROM programmer is a good idea.

Thanks for the tips, I never thought of trying it without the chip installed. I may give that a shot later on. I really do need to get a programmer eventually. When I do I'll get some extra EEPROMs in case this one is faulty which it seems like it may be. For now I found something even better that I didn't even remember I had, a DTC EIDE Ultima Pro card. I installed it and it detected my CF card immediately and booted right up; also seems to be much faster than the XT-IDE anyway. I guess that makes sense, it's a 16-bit card after all. I'll try to get the XT-IDE fixed eventually and put it in my IBM 5160 which is what it was really meant for anyway.

Just a reminder that when properly configured, the xtide xub does not care which IDE controller your drive is sitting on. This is not the case with Promise IDE controller bios.

It is this feature which makes an old nic with a bootrom socket an acceptable means of adding the xub to an arbitrary computer.

Consider for instance, a late pentium system, with a pnp bios, and an sb32 with an ide interface.

The pentium system's int13 implementation is just fine, but adding the xub lets you drop 2 more hard drives on the soundblaster's IDE controller, which the system's bios does not look for or set up drives on. They'll be limited to 16bit IO, but that's not a big deal for certain kinds of drive, like LS120 (ata model, not atapi model), or for 'it's bulk storeage, and does not need to be fast' situations.

Make sure to disable BIOS shadowing when reprogramming the XTIDE in-system. Had that error a few times.

I'm not sure if BIOS shadowing is even an option in this Dell BIOS, it's pretty spartan (Dell 333S/l). Maybe that was causing the problem. I do have a 3COM 3C905B PCI network adapter with a socket, so perhaps I could throw it in my Optiplex and try flashing the chip from it. Probably worth a try.

I thought I had another problem when I realized I couldn't write to my CF card at all from this EIDE Ultima card, it was just working as read only. Any attempt to save a file threw an I/O error. Turned out to be a simple fix, I just had to plug in a berg connector to my CF adapter to power it; apparently this old IDE card doesn't provide what it needs. I also found another post here about a newer BIOS for this DTC card that extends it's support up to 32GB, so yet another reason to get a programmer someday.

Also, don't forget that you need to configure the BIOS before flashing it... Follow this series https://youtu.be/lnb6zamDI6A?si=j84yk_J7y160JJB3