I may have tried this exact thing a few years ago without LLMs, though I can no longer remember if it was a ThinkPad X61 or not. I just know it was an Intel ICH that wasn't supported by Coreboot and wasn't documented at all. I tried for quite a while and getting it to output anything to the serial port was very exciting for me, but at that point I definitely hit a wall: the RAM initialization and other platform init was a complete mystery and the only way I was going to learn about it was by reverse engineering the BIOS, since it wasn't documented. Ultimately I just never found the time to get to it, so it never happened, which still to this day feels like a shame.

What a mixed blessing it is now that theoretically, especially as LLMs increase in competence, an idiot like me might actually be able to port Coreboot to an unsupported platform with some LLM-assisted reverse engineering. I mean, it's probably still a long shot without as much arcane knowledge as you gain from working in stuff like this professionally, but at this point it's probably the best shot I have since I probably won't find myself in such a scenario.

I guess I should try to find time to revisit a reverse engineering project that I haven't had time to dig deep into... It does feel like a shame that this way I'll never really improve my skills related to reversing, though.