Another thought I had, is that we need to see the dump of the /dev/sdd to look for missing partitions there. Looking at the dump of /dev/sdc, I see the markers for an EFI label, but maybe that's the problem? It was possibly a DOS partition table before? It's a shame you don't have any logs of the system booting up from before the motherboard swap. Or do you? You say the root volume came up just fine. Can you trawl through there for old data in /etc and /var? You might have some details in there which would help. But I'd also be leery of making any changes to sdc and sdd without either A) copying the disk to another disk, or B) using overlayfs so that you don't muck it up by accident. So if you can do: sudo dd if=/dev/sdd bs=4k count=4k |hexdump -C |head -n1000 And we can compare the output of both /dev/sdc and /dev/sdd, that might help alot, since they were supposed to be mirrors of each other. John
