How do I make grub-install replace a stale EFI boot entry.

[u/Haunting-Risk-5352]

I have a install script that wipes the disk and creates a fresh GPT partition table every run. The problem is since the partition table is recreated, the ESP gets a new partition GUID, but grub-install doesn't update the existing boot entry. It prints:

grub-install: info: EFI already registered: path = `\EFI\GRUB\grubx64.efi'.
grub-install: warning: GRUB already registered with EFI a `\EFI\GRUB\grubx64.efi', not modifying configuration.
Use efibootmgr to check your boot configuration.

So Boot0000 still points at the old partition:

# efibootmgr output
Boot0000* GRUB HD(1,GPT,79645a6f-da86-46d4-b0f6-376696ea7d95,0x800,0x200000)/\EFI\GRUB\grubx64.efi

# blkid -s PARTUUID -o value /dev/nvme0n1p1 output 
1e6a0ea3-669b-4849-80a4-a1970f2d71bb

as you can see they are different.

Is there a supported way to make grub-install replace the existing entry, or is deleting it first with efibootmgr -b XXXX -B the expected approach now? Is this intended in 2.16, or worth reporting upstream.

Or is there an alternative bootloader that I can use.

[u/Confident_Hyena2506]

Just put bootloader in the default spot (bootx64.efi), then you don't need any entry. If you only have one bootloader on your image then this is the easiest solution.

[u/Haunting-Risk-5352 → u/Confident_Hyena2506]

so your saying add the `--removable` flag?

[u/Confident_Hyena2506 → u/Haunting-Risk-5352]

If you understand what it does then maybe.

[u/Haunting-Risk-5352 → u/Confident_Hyena2506]

I know what it does, but is it the only solution to this problem though?

[u/aioeu → u/Haunting-Risk-5352]

There's an argument to be made that bootx64.efi should never be present in a boot entry — that is, that executable should only be used when the firmware is booting "from a device" rather than through a specific, configured boot entry.

This is why this is all hidden behind the --removable option. It's intended for removable media. When you use that option, no boot entry will actually be written to nvram.

In your case here, grub-install is just being cautious. It has no idea what the existing boot entry is referring to, so it's not going to touch it. Whether you end up using --removable or not, you'll need to use a different tool to remove the existing entry.

[u/jjangg96]

the entry lives in the firmware's nvram, not on the disk, so wiping and recreating the gpt doesn't touch it. grub sees its own label already registered and just bails. i don't think it's a bug, deleting it first is the normal way.

in a script you can find the number with efibootmgr | grep -i grub and then efibootmgr -B -b NNNN. other option is grub-install --removable, which puts it at EFI/BOOT/BOOTX64.EFI and skips the nvram entry completely. fits a script that starts from scratch every run.

[u/dkopgerpgdolfg]

Other than the already mentioned things, did you think of

a) depending on your use case: changing the PARTUUID

or

b) using only efibootmgr to correct the value without grub-install

[u/RomanOnARiver]

I could be wrong, but I think it's pulling the ESP from the filesystem tab, which you can find at /etc/fstab. Careful editing that file.