This project reminds me of a cyberpunk SF story, in which (something like) some super elite hackers, needed for a special job, chose gear old enough to be impervious to the adversary they were facing. (Not cyberdecks contemporary of the setting, but something more like modded Nintendos, which the black ice wouldn't know what to do with.)
I also had that story in mind several years ago, when the Intel Management Engine ridiculousness ticked me off, and I went to a lot of trouble to make and store half a dozen Libreboot X200 "decks".
(Though I don't do 31337 things, so I mostly only ended up using one such deck to keep an eye on my 401(k) account.)
I one purchased a Coffee Lake SFF PC from eBay from a fleet reseller, and I discovered a "ME DISABLED" sticker on the chassis when I received it.
Sure enough, every single software tool, or the BIOS/UEFI itself suggests ME is disabled, or does not exist at all. 'Features' requiring ME like Intel SGX appear as not supported.
I'm not sure how exactly they did it, and/or if there are any other modifications made to the system, but digging further is beyond my skill level.
My theory, with no evidence, is that this is an ex-govt (security/defense?) PC that somehow got sold.
IIRC, there was a non-publicly-known switch to turn off IME, for government purposes, which became publicly-known. There have also been efforts to delete just part of IME from the flash. A couple links:
On X200-era systems, however, you can remove IME entirely from the flash, which is what I did. I put only Coreboot and GRUB2 on the flash, but you can add SeaBIOS to that, if you want more PC BIOS facilities and options available.
(So I stockpiled a few backup units of the X200, before they disappeared from the market, or the available units got too beaten up or expensive.)
I seen to recall having some Thinkpads which had a firmware setting that would irrecoverably break the management engine. It had a lot of scary warnings about disabling it, and likewise features like SGX wouldn't work properly from what I could tell. I think they were T460S'es, but I could be misremembering.
I also had that story in mind several years ago, when the Intel Management Engine ridiculousness ticked me off, and I went to a lot of trouble to make and store half a dozen Libreboot X200 "decks".
(Though I don't do 31337 things, so I mostly only ended up using one such deck to keep an eye on my 401(k) account.)