Force shutdown somehow nuked GRUB from orbit

My ThinkPad runs Fedora Silverblue 43. Today I found myself unable to wake it from sleep. This has never happened to me before. I forced a shutdown by holding the power button, but the computer wouldn’t start again for several minutes; for some reason it decided it had to retrain the RAM. Very confusing.

When it finally booted again, I was taken directly to Windows. GRUB no longer appeared as a boot option. I booted SuperGrub2Disk from a live USB, and it found the Fedora GRUB EFI stub. I loaded it and was greeted with my familiar Fedora boot menu—but selecting either of the two Fedora entries available immediately gave an “out of memory” error!

I then tried booting into a live USB image of Fedora Silverblue 43. I selected “Rescue a Fedora System,” but it couldn’t find my Fedora install.

How can I put my system back in working order? I don’t understand what got deleted, let alone how. Help!

It shouldn’t try to retrain the ram for no reason, perhaps did a long POST due to some hardware failure? I’d suspect the ssd first, could it be failing? check ssd logs with smartctl.
you are very likely on btrfs and it’s very reliable, forced unsafe reboot is not enough to do such harm.

I am indeed on btrfs. But how would I run smartctl if I can’t even get into my Linux install?

I highly doubt it’s an SSD failure, as the laptop is only about six months old.

Based on the symptoms (strange blinking patterns on the Esc, F1, and F4 LEDs for several minutes), I’m fairly confident it was in fact retraining the RAM. I couldn’t find any other documented reason those blinking lights would happen. I don’t believe it was an error code, because the pattern was not consistent.

you can live boot from any linux distro and start it.
if it’s KDE then just go to settings - system information - smart status

How did you install Silverblue alongside Windows? For Fedora Atomic it is recommended to have a distinct /boot and /boot/efi partition.

Can you boot a live ISO and post the output of lsblk -f?