Thanks for replying.

Most of the information I’m finding about this flavour of arch doesn’t reveal much about libreboot’s role in this issue. I’m not familiar with the device and online results are vague about what the specs are.

My main thought is If you’re using a Nvidia GPU or other proprietary software to run hardware, did you reinstall its software after changing the kernel? I’m not sure if your distro automatically does that for you.

I do not believe I reinstalled any Nvidia drivers but I am unsure. I do have the linux-firmware-nvidia package installed. I am just using the integrated graphics that are on the X200S. Maybe that's part of the issue considering it released around 2008?

Are you using shim for anything?

I’m wondering if something went funny with your mok enrolment or if it failed to use the key to sign the module? Could test by temporarily disabling secure boot. (But would continue to fail if not the problem; such as the modules are compiled against the wrong kernel)

If by shim you are referring to the EFI preloader I do not have it installed.

My other thought was that I’m under the impression that endeavourOS uses pinned versions and swapping out the kernel puts you in an undefined state.

You might have some luck jailing it on an working os with the configuration you desire and regenerating the boot files. Same idea as using the rescue environment on a livecd. The last time I had this idea it was a big waste of effort. When I realized I could just roll back using a backup.

I am not too sure about how to test this.

Edit: maybe the drive is dying try testing it?

I have my doubts that it is the drive considering it seems to work fine within initramfs. I can run my X200S for days without issues as long as I boot that way.