I think with only that, you'll have to go look at "XT booting" videos on youtube and hope you get lucky.

Even back then, this kind of BIOS was quite seldom to see.
Get an EPROMMer and just try out BIOS dumps you'll find on the web.
You can exchange almost all of these, as the real XT compatibles do not have chipset specific BIOSes.

turbooo wrote on 2021-11-15, 10:11:

Does this sound familiar to anyone? Unfortunately I don’t have any other useful details, I remember two half height floppies and no hard disk, and CGA graphics but don’t think that’s particularly helpful in narrowing things down.

With two half-height floppies and CGA graphics, you're on the right track in thinking it was an XT clone. The most common BIOSes would be the Phoenix and Award ones, but they don't have a POST screen like you describe, so my guess is that your machine would be one of the "branded" systems e.g. an Amstrad PC1640 or similar.

retardware wrote on 2021-11-15, 18:15:

Get an EPROMMer and just try out BIOS dumps you'll find on the web.
You can exchange almost all of these, as the real XT compatibles do not have chipset specific BIOSes.

Yep! The XT clones were (for the most part) pretty much identical to the genuine IBM XT 5160, so you really can swap out the BIOS and expect things to still work. It's kind of fun to boot a genuine XT 5160 motherboard using a Phoenix clone BIOS...

I don't think you need to go so far as programming EPROMs, just use an accurate emulator like PCjs or pcem and try out the various BIOS images floating around. Here's a starting point with some ROM dumps of various XT clones:
http://www.minuszerodegrees.net/rom/rom.htm
http://www.minuszerodegrees.net/xt_clone_bios … _clone_bios.htm

kdr wrote on 2021-11-16, 19:14:

With two half-height floppies and CGA graphics, you're on the right track in thinking it was an XT clone. The most common BIOSe […]
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turbooo wrote on 2021-11-15, 10:11:

Does this sound familiar to anyone? Unfortunately I don’t have any other useful details, I remember two half height floppies and no hard disk, and CGA graphics but don’t think that’s particularly helpful in narrowing things down.

With two half-height floppies and CGA graphics, you're on the right track in thinking it was an XT clone. The most common BIOSes would be the Phoenix and Award ones, but they don't have a POST screen like you describe, so my guess is that your machine would be one of the "branded" systems e.g. an Amstrad PC1640 or similar.

retardware wrote on 2021-11-15, 18:15:

Get an EPROMMer and just try out BIOS dumps you'll find on the web.
You can exchange almost all of these, as the real XT compatibles do not have chipset specific BIOSes.

Yep! The XT clones were (for the most part) pretty much identical to the genuine IBM XT 5160, so you really can swap out the BIOS and expect things to still work. It's kind of fun to boot a genuine XT 5160 motherboard using a Phoenix clone BIOS...

I don't think you need to go so far as programming EPROMs, just use an accurate emulator like PCjs or pcem and try out the various BIOS images floating around. Here's a starting point with some ROM dumps of various XT clones:
http://www.minuszerodegrees.net/rom/rom.htm
http://www.minuszerodegrees.net/xt_clone_bios … _clone_bios.htm

You're probably right about the branded Bios and the links will hopefully be helpful to OP. Restoring an Amstrad atm I don't think the described behavior fits these xt machines but of course it could be some other similar machine. I had some Olivetti XTs but can't remember the POST they had. You can see there's no memory test and view the design of the Amstrad on YouTube, for example this vid about 5min in: https://youtu.be/re40EEKHAqU