After system upgrade to 22.04 (from 20.04) system is not bootable. It complains that it can't find /dev/mapper/ubuntu--vg-root and defaults to an initramfs shell // BusyBox.
I believe there was an issue during upgrade due to /boot being too full, which was in a separate partition (in the meantime, I have moved /boot to the root folder using instructions found here: https://visualplanet.org/blog/?p=460 )
Initially I followed the instructions found here, which lists what seemed a very similar problem: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1313169 , but it had problems when installing grub.
Also checked this very similar post: System boots to initramfs after upgrade from 21.10 to 22.04 . Partprobe not available on BusyBox, so no success.
I can chroot into the system from a LiveUSB without trouble, and I have made a backup of the data. I have also since updated all packages. Ubuntu is the only system installed.
I have also tried to use the boot-repair tool, unsuccessfully. Full output of boot-repair can be found here: https://pastebin.ubuntu.com/p/YTtf85ty4T/
I have been trying so many things that I have admittedly lost track -- I think the best start would be the output of boot-repair to get a picture of the current situation.
Last attempt was creating a EFI partition following this: https://wiki.ubuntuusers.de/GRUB_2_von_BIOS_nach_EFI_umstellen/
It all seemed to go well, but... surprise, didn't boot. No change. Tried to use boot-repair again to no avail, here's the output: paste.ubuntu.com/p/JQyBxhdsJh
Where's the issue? Haven't been able to start my system for two days, and I'm in great need! Thanks for any tips.
