Laptop Keyboard not working after kernel loading - HP Spectre 360x

Hello everyone!

I have a HP Spextre x360 - 13-w010 laptop. I’ve had it for years and EndeavourOS was working flawlessly for at least 3 years.

Until, in June (2024), the laptop’s integrated keyboard and mousepad, as well as the laptop’s touchscreen, stopped working. External keyboards (USB) work fine. I suspect this started after a kernel update. (I’ve always used the ‘normal’ kernel, not the LTS).

The keyboard stops working as soon as I need to enter my LUKS decryption password.

Everything works fine in the BIOS (which is password-protected, and I can enter the password without issues), and also when I run a windows bootable installation USB, keyboard and mousepad do work as expected.

The Linux-based live USB sticks I tried do not work. (Mint and Ubuntu).

I installed the LTS-kernel, selecting this in systemd-boot makes no difference.

I read quite a few topics on this forum and on other places around the internet.
Loading kernel options seems to be my best bet, but I don’t exactly know how to do this. So I have a few questions about this.

Which kernel options would I be recommended to try?

Also: do I have to add “=1” (so add “i8042.reset=1”) to the options I try?
So I would add this to the end of the options line?
(I use systemd-boot)

I do understand that if I find ‘the option’ that works, I think I should add it to /etc/kernel/cmdline and then reinstall the kernels.

If the keyboard worked well for years, how likely is it that it will start working again without the need for kernel options? It’s not been working for a little under half a year now; I’m also very surprised that live environments based on older kernels (such as Ubuntu) don’t work either.

Thank you all very much in advance for any ideas or suggestions you might have!