Re: BIOS_grub GUID signature within an EFI partition?

[Goh Lip]

On 12/09/2023 06:51, Moses Gold wrote:
> The BIOS_grub GUID signature:
> "48 61 68 21 49 64 6F 6E 74 4E 65 65 64 45 46 49 -- Hah!IdontNeedEFI"
> is contained within my EFI partition after a recent grub install (grub and
> EFI added during same Linux installation). Specifically, the EFI partition
> begins at sector 1 of my boot device /dev/nvme0n1 and the BIOS_grub
> signature appears at sector 2. gdisk says the following:
>
> Number  Start (sector)    End (sector)  Size       Code  Name
>     1            2048         1628159   794.0 MiB   EF02
>
> Is this the normal predicted configuration of BIOS_grub with an EFI
> partition?


Yes, ‘0xEF02’is the correct code for the bios_grub partition in a GPT
disk for a bios_legacy boot.

However when installing grub, it must be booted in grub-legacy to
proceed with a grub-legacy install.
Nevertheless, if booted in uefi, it can still be installed in
bios-legacy if the install command has the parameter "--target=i386-pc"

sudo grub-install --target=i386-pc --boot-directory=/boot /dev/sda
--recheck --debug

You said "(grub and EFI added during same Linux installation)".

You have installed in grub-efi in your recent installation. You cannot
mix efi and legacy install in the same disk (but you can in the same
system with different disks but I won't recommend that either).