Qubes Suddenly Won't Boot

I’ve been using Qubes for over a year now consistently as my daily driver, so it can’t be a hardware compatibility issue. A couple days ago I shut it down like usual and since then it refuses to boot up.

For a while, I wasn’t even getting any signal to the monitor and couldn’t access BIOS. Was thinking it was a problem with my mobo until I tried attaching the monitor directly to the PC (I use a KVM switch between my PC and an employer-provided Windows laptop). That finally got me into the BIOS and it clearly recognizes the SSD I have Qubes installed to as a boot device as it shows up in the boot order list, but it doesn’t boot from it. It just goes to black and requests a valid boot device be attached. I’ve made sure that SVM and IOMMU are both enabled and Secure Boot is disabled supposedly (it’s an ASUS motherboard, so there’s no Secure Boot toggle; just an option between “Windows UEFI mode” and “Other OS”). I’ve tried booting into a live session of Debian and that works just fine. I’ll try a live session of Qubes later on today to see if I get the same result. I’m hesitant to reinstall though as I have some unarchived files on the hard drive.

The only thing I can think is I was experimenting with adding a second monitor a couple weeks ago. That brought me some boot trouble for some reason, but it usually does when I’m playing around with cables. It was quickly resolved.

Btw, the SSD is brand new Western Digital, ~320 GB. Bought it last year specifically for installing Qubes on.

Maybe the problem is the missing EFI boot entry so you can try to fix it like this:

Tried this, but when I issue the efibootmgr commands, it responds with EFI variables are not supported on this system.

If I try to continue with the mount, it redirects me to the shell with the message You don't have any Linux partitions. Rebooting.

EDIT: I decided to just do a fresh reinstall; though will probably wait for 4.1.1 to come out as it should be any day now. Obtained copies of my unsaved files on the encrypted drive following the instructions here. In the meantime, I have a laptop to use in the mean time.