grub2 – Boot error: Failed to open \EFI\ubuntu\grubx64.efi

I’ve got a Lenovo Thinkpad X220 running Ubuntu 22.04, and it’s recently stopped booting successfully. (FWIW, it’s an old laptop I gave to my son as hand-me-down, and yesterday he dropped it. So that could be part of the problem.) On startup, it gives me the following error message:

Failed to open \EFI\ubuntu\grubx64.efi – Device Error
Failed to load image \EFI\ubuntu\grubx64.efi: Device Error
start_image() returned Device Error

I was able to successfully boot from a boot-repair USB, and got the output at the following pastebin: paste.ubuntu.com/p/qpQnmZsz8k/

The only thing that seemed like an obvious red-flag (to my non-expert eyes) was that “No boot loader is installed in the MBR of /dev/sda”. I tried a to use boot-repair to repair the filesystem, but this got me the same result in the end.

When I ran sudo fdisk -l, the output for sda (my Linux filesystem) included “The backup GPT table is corrupt, but the primary appears OK, so that will be used.”

I tried to address the missing bootloader problem by reinstalling GRUB using the instructions here, but when I came to the critical step (running grub-install) I got a bunch of error messages reading:

error: cannot read `/dev/sda’: Input/output error.

It just sort of churns along, repeating that error message over and over. After a few minutes, I got the following:

grub-install: warning: File system `fat’ doesn’t support embedding.
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged..
grub-install: error: will not proceed with blocklists.

I’m officially out of my depth here. Any ideas on how to proceed?