I recently replaced a smashed screen on a HP Spectre x360 G2, running Ubuntu 20.04LTS. However, after booting up again I had lost the use of the laptop's touchpad and keyboard (NB. devices still functioned in the BIOS, but lost function after GRUB). There are many similar questions floated here1, here2, here3, here4, here5, here6, and here7. I have followed all these prompts - most suggest (re)installing
xserver-xorg-input-all but it was all up to date, no changes.
The last link offered some help: by switching ACPI off in the GRUB settings (edit
quiet splash, and updating GRUB as advised). This reverted to old APM and I regained control of mouse and keyboard. However this came with other issues - namely, the kernel has no access to power status, and the keyboard was primitive (none of the special keys worked, e.g. volume/brightness).
I also tried upgrading to Ubuntu 20.10, and that brought other issues - namely it was unbearably laggy. (But I think it had full functionality).
Anyway, after a clean install of 20.04, the problem persists. Can anyone offer some advice?
Edit: Also found this related post, which and tried
intel-vbtn. In the answer from @IGR94, they mention this won't work for a
/sys/class/dmi/id/chassis_type of 31 or 32. Mine is 31, which explains why that answer does not solve.