jord1981; Youch !
Three things pop into my mind at this time.
a) Have you tried resetting bios to defaults with all drives hooked up ? Maybe bios will remap the drives .
b) Verify that the UUIDs of all partitions are correct, and none are duplicated, and all match up .
c) The use of "device.map" file has been depreciated, however, I had to use that file to get my system to boot properly, after I moved drives around. Took me forever to figure that one out !.
Does this file exist on your system:
and let's see what the map file contains.
ls -la /boot/grub/device.map
##and if it does exist:
Might consider generating that file for the system to use.
inquiring minds want to know