omg I did something similar. I had a power outage, and my secondary server wasn’t booting up anymore. i dont have a monitor in the server room, so I brought it back to my room to try figuring out what was wrong with it. the bios screen always said smth about “no media attached, check hard drive cable”, so after checking the hard drive I came to the conclusion that my boot partition got messed up. i spent the next few hours fiddling with grub on a recovery disk to do stuff. i dont have a clue how Linux partitions work so i probably messed up more stuff than i started with, but in the end i had everything nearly done successfully. but the server wouldn’t boot still. turns out all that happened was the power outage zapped the motherboard battery and i lost my settings (and turned off uef booti). twas solved with 30 seconds of fixing the boot settings and 30 minutes of swapping the battery. so I manually fixed my grub boot partition for hours for no reason