Couldn't Mount Efi partiion (resolved), and also cannot post without clearing CMOS

I am not the most experienced with linux, and really wish I had the forethought to take some pictures. This is what I experienced today, and could really benefit from some guidance.

Today, I decided to do a system update with pacman -Syu. There were some keychain issues that I resolved with, to the best of my memory the following:

rm -rf /etc/pacman.d/gnupg
pacman-key --init
pacman-key --populate
# i was running into errors still so I updated the keyring packages
pacman -Sy archlinux-keyring endeavouros-keyring
pacman-key --refresh-keys

The last command had a lot of errors, but afaict this is part of the normal process as it tries various sources for updated keys.

This finally fixed the issues with pacman -Syu, so I rebooted.

I posted fine, but when booting through systemd , the system was unable to mount Efi. systemctl status efi.mount in emergency mode showed a message unknown type of file system [vfat]. I rebooted again just to check, but this time I was unable to post.

After some finagling, which include resetting UEFI settings, clearing CMOS, and flashing a new updated UEFI, it seems I am only able to boot cleanly after I clear the CMOS. Throughout this process, there was a lot of hanging on screen freezes, whether it freezing after allowing the system to auto-boot, freezing when booting to a specific target from UEFI, that required me to shut down the pc by holding the power button, which I’m afraid damaged something.

Finally, I was able to follow another thread here and realized that somehow, the efi partition and root partition uuids’ had changed as they were displayed in blkid. Updating /etc/fstab, /etc/kernel/cmdline, and verifying the *.conf entries in the mounted efi partition worked, and I’m now able to boot.

The questions are this:

  • What can cause a UUID to change like this? These drives have honestly been through the multiple reinstallations, and a windows installation, so it’s very possible that this is some weird behavior due to residual efi partition? Not sure if that’s possible
  • Could anything I did here create a persisting hardware problem? I have removed the cmos battery from my machine’s motherboard in the meantime since I do not have any UEFI options set, but I’m considering seeing if I can get this RMA’d and would like to avoid something like this in the future.

Any insight would be appreciated

Generally speaking, you need to make filesystem changes to change the UUID of a partition. An update would never change a UUID. Even BIOS/firmware updates shouldn’t cause a UUID to change.