Recreate EFI partition

shirshendu · September 10, 2023, 5:53am

Recently I installed Debian 12 in a machine with EndeavourOS and the efi partition was overwritten (due to my carelessness). The structure of the partition was

/boot/efi/
└── EFI/
   ├── boot/bootx64.efi
   └── EndeavourOS/grubx64.efi

By running the command
sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=EndeavourOS --force --recheck
I was able to recreate the EndeavourOS/grubx64.efi
But how to recreate the boot/bootx64.efi ?

pebcak · September 10, 2023, 7:05am

you could add --removable to the grub-install command if you want

sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --removable --recheck

Tip: If you use the option --removable then GRUB will be installed to esp/EFI/BOOT/BOOTX64.EFI (or esp/EFI/BOOT/BOOTIA32.EFI for the i386-efi target) and you will have the additional ability of being able to boot from the drive in case EFI variables are reset or you move the drive to another computer. Usually you can do this by selecting the drive itself similar to how you would using BIOS. If dual booting with Windows, be aware Windows usually places an EFI executable there, but its only purpose is to recreate the UEFI boot entry for Windows. If you are installing GRUB on a Mac, you will have to use this option. If you execute a BIOS update, this update might delete the existing UEFI boot entries. Therefore, it is a potential fallback strategy to have the “removable” boot entry enabled.

source: https://wiki.archlinux.org/title/Grub

shirshendu · September 10, 2023, 7:29am

Thanks : )
Two small queries -

How does calamares do this during install? Couldn’t find the option “–removable” in UEFI grub install in /usr/lib/calamares/modules/bootloader/main.py
boot/bottx64.efi and EndeavourOS/grubx64.efi are exactly same in size? so are they the same with different names? if yes, then will copying one to the other work?

pebcak · September 10, 2023, 7:55am

I am not familiar with all the Calamares’ ins and outs but I did take a quick look and found this:

github.com

endeavouros-team/calamares/blob/fce0aed30cb816ccb87bca2555a1094970f51a50/src/modules/bootloader/bootloader.conf#L77


      
          # These words must be at the **end** of the *efiBootloaderId* value.
          # There must also be at most one of them. If there is none, no suffix-
          # processing is done and the *efiBootloaderId* is used unchanged.
          #
          # NOTE: Debian derivatives that use the unmodified Debian GRUB EFI
          #       packages may need to set this to "debian" because that is
          #       hard-coded in `grubx64.efi`.
          #
          # efiBootloaderId: "dirname"
          
          # Optionally install a copy of the GRUB EFI bootloader as the EFI
          # fallback loader (either bootia32.efi or bootx64.efi depending on
          # the system). This may be needed on certain systems (Intel DH87MC
          # seems to be the only one). If you set this to false, take care
          # to add another module to optionally install the fallback on those
          # boards that need it.
          installEFIFallback: true

Perhaps @dalto could shed some more light on this?

I guess you could do this as long as you rename the file and use the correct alternative boot path. However for it be “bootable”, I think you would need to write the boot entry to NVRAM manually using efibootmgr.

shirshendu · September 10, 2023, 10:58am

Thanks a lot

lorebett · September 10, 2023, 12:14pm

But this way you wouldn’t get EndeavourOS/grubx64.efi.

I mean, you have to run both commands if you want both files.

pebcak · September 10, 2023, 12:16pm

OP had already done:

lorebett · September 11, 2023, 11:46am

IIRC, it doesn’t do that by using grub: the installer “manually” copies that file

system · September 13, 2023, 11:46am

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