Background: I recently had a spill that damaged my Dell XPS 13 Developer Edition, which was preinstalled with Ubuntu 16.04.
My motherboard has been replaced. I removed the SSD before repair; now I've put it in again and I can't boot anymore - I don't even get to grub; I just get a "No bootable device found." error and can go no further.
I hit F12 on startup and try booting from the UEFI partition. When I do this, I get an error from initramfs: "Unable to find a medium containing a live file system".
I tried setting up a USB with Boot Repair. I can boot up with this, and from there I can see that the correct partitions are still there and the Ubuntu partition still looks good on /dev/sda4.
dev/sda1 is the EFI system partition. I can mount /dev/sda4 just fine.
But how do I get the system to boot correctly again?
Thanks in advance.