Comment 25 for bug 1970402

I have an Asus G752VY and encountered this issue when upgrading from Kubuntu 20.04 to 22.04 this morning. Neither my new kernel nor my old one would boot, whether into recovery mode or not. I ended up spending a lot of time figuring out how to fix it through the USB live disk.

While I know this is a bug tracker and not a how-to guide, I'm posting the steps I used to recover because this is one of the first results that comes up in Google for this problem and I'd hope to save others from my hours of frustration this morning. My root partition is on /dev/nvme0n1p1, so you'll need to adjust if yours is elsewhere.

1) Boot USB disk and select Try It.
2) Open a command line.
3) sudo mount /dev/nvme0n1p1 /mnt
4) sudo mount --bind /dev /mnt/dev && sudo mount --bind /proc /mnt/proc && sudo mount --bind /sys /mnt/sys && sudo chroot /mnt
5) Use your favorite command line text editor to edit /etc/initramfs-tools/initramfs.conf as noted above. I used:

MODULES=dep
COMPRESS=xz

6) For safety, I made a backup copy of my existing init file, not that it worked in the first place, but it seemed smart.
7) update-initramfs -c -k all
8) update-grub
9) Reboot system.

With all of that, it booted successfully. Hope it helps someone.