Assuming this is an ATX or ITX PC, there’s likely a way to reset UEFI so you can disable fastboot and change your settings, or at least boot from a recovery USB.

There’s usually something like a button or 2 pins you can short on your motherboard to reset the settings. If your machine has dual BIOS, there will be a switch you can flip, though you’ll probably need to update the UEFI again once you do that.

In the worst case (and this should work on almost any device), remove the CMOS battery, let the device sit for a few minutes, then put that battery in. That should clear all settings, including fastboot, and allow you to do recovery stuff - just make sure you fix the time before going on the internet.

Try disabling TPM in the bios/uefi by spamming DEL or ESC or F10 or F12 or F9 or ENTER

Do you have GRUB? If yes you can edit your kernel command line and append “init=/bin/bash”, see if at least this gives you a prompt, this has saved me a couple of time in the past. Else booting on a USB and mounting your boot partition may help to fix it.

BTW I also have LUKS and I’m using TPM, using tpm2-initramfs-tool, first, it failed because I forgot the tpm modules in initrd, but I always have 2 kernels installed and only modify one initrd at a time to have a safe boot if I have a problem, like I had!

I tested tpm2-initramfs-tool with proper tpm2 modules and it worked.

I also tested with clevis-initramfs and clevis-tpm2 and it’s even easier, no messing with crypttab.

Also, as long as you can break GRUB and append “init=/bin/bash” it is not secure of course, you can then prevent grub editing or not using grub at all.

Perhaps an issue with the TPM, try disabling it to see whether it boots up.

I had this same error a few months ago when a drive was failing to mount because (unbeknownst to me) it was overheating. I turned the system off for a few hours before troubleshooting (I had errands to run). When I came back, the system booted without issue.

If you’re looking for an easy troubleshooting step, have you tried turning off the system for several minutes (and unplugging it) and then powering it back on?

I had this issue and it was because I told grub to support dual booting from two different disk drives (one of them USB) and then I removed the USB drive. Linux-boi still tried to enforce booting from the now not-connected drive.

I can’t remember exactly what I did, but there may be something about a systemd unit which can be removed/disabled - or maybe I did some fishing around in fstab to remove the drive it thought should exist but wouldn’t always (and then probably did an update-initramfs -u or similar.