I have a PC whose drive configuration is as follows:
I have written a bash script to keep the three ESPs in sync whenever a kernel package is installed, upgraded, or removed. Prior to running it however I thought I would have a quick look at the output of efibootmgr to see how things are currently laid out before I go ahead and add other entries for my second and third ESPs.
Debian Buster was installed on this PC, and so I was expecting a single boot entry to be added to UEFI NVRAM by the installer, but instead when I look there are three - one of which make sense, and two of which are very strange indeed.
Lets start with the sensible efibootmgr entry:
Boot0000* debian HD(1,GPT,5dd0d6c2-bc67-4669-93a1-0a6fc5ffc8f4,0x800,0xf3800)/File(\EFI\DEBIAN\SHIMX64.EFI)
Here the third bracketed field (5dd0d6c2…) is the UUID of /dev/nvme2n1p1, which is one of the ESPs. The small grub.cfg file in the EFI/debian directory of this ESP contains little but the UUID of /dev/md0, which as can be seen from the diagram above is where the boot partition is located. So far so good.
Contrast this to one of the strange efibootmgr entries:
Boot0005* debian HD(1,GPT,ba7bb369-d85e-42fe-831b-729764ae76da,0x800,0xf3800)/File(\EFI\DEBIAN\GRUBX64.EFI)..BO
This time the third bracketed field (ba7bb369…) is the UUID of /dev/nvme1n1p1, which again is one of the ESPs. The problem is that the small grub.cfg file in the EFI/debian directory of this ESP contains little but the UUID of a device that does not seem to exist! The line in question from the grub.cfg file is:
search.fs_uuid d8435b7e-978a-4a1b-9620-01e9c2621302 root lvmid/Z7v4zP-ia4C-rJLq-UIcW-il13-CdmB-PI03p3/xRoZse-kSZx-L9Mb-9wC2-nuJF-qesr-DRvzrx
Now I have looked at all the /dev/disk/by-blah entries, and looked carefully at everything listed by blkid and I cannot find a single reference to this UUID anywhere.
Is anyone able to shed light on what is going on with this strange entry? I believe I could simply delete it and the other strange entry, and add new entries for my second and third ESPs as planned, but I would really like to know why these strange entries were added by the installer, as they do not make any sense to me…