No mouse, Wi-Fi (or much else really) after rebooting Ubuntu 24.04 LTS

I rebooted my functioning laptop, running Ubuntu 24.04 LTS, Thursday night. When it booted again, it had no detected mouse/trackpad, Wi-Fi, ethernet, Bluetooth or soundcard. Fairly limiting experience. Do not recommend.

Several reboots and power cycles didn’t make any difference.

Failed attempts at rolling back kernel

It was suggested to me by people more experienced with Linux than me, to attempt to roll-back the kernel. The methods I found involved listing installed kernel versions by running:

dpkg --get-selection | grep linux-image

However that yielded no results. Another suggestion was to select “Advanced options for Ubuntu” in the GRUB menu, but that wasn’t available to me. I did try selecting “Fallback on failed updated”, which seemed to make no difference.

Maybe these options or not available to me due to having SecureBoot/UEFI enabled?

In the /boot/grub directory, I found kernel.efi to be a symbolic link to pc-kernel_2247.snap/kernel.efi. To my relief, I found what I assume is a previous kernel version, pc-kernel_2352.snap/kernel.efi.

I updated the symlink to point to this older kernel, but ufortunately - as I was soon to find out - using the absolute path, instead of the relative path. After restart my computer was now completely unbootable.

By now, I had given up on it, and was mentally preparing to reinstall, and set SecureBoot to “install mode” in the BIOS - which I suspect my not be necessary at all?

Salvation!

Before beginning to reinstall, I came across a fellow Ubuntu user, also using TPM-backed full-disk encryption (FDE), who seems to have encountered the same issue around the same day.

The solution seems simple - just run:

sudo snap revert pc-kernel

So, I toggled SecureBoot install mode off again, booted a live Linux disto and fixed the symbolic link to the (newer) kernel, allowing me to boot again. I don’t know if I could just have pointed the previous kernel.

However, now I had tripped TPM, requiring me to enter the 47 character long LUKS recovery key. It took a few failed attempts until I realised the key contains hyphens ("-") and that the prompt was probably using US keyboard layout.

At last, my computer was able to boot again with full hardware support!