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# GRUB EFI Examples

From ArchWiki

Summary
It is well know that different motherboard manufactures implement UEFI differently. The purpose of this page is to show hardware-specific methods known to work when installing/restoring GRUB in efi mode.
Related Articles
Grub

## Apple Mac EFI systems

### Generic Macs

Use bless command from within Mac OS X to set `grubx64.efi` as the default boot option. You can also boot from the Mac OS X install disc and launch a Terminal there if you only have Linux installed. In the Terminal, create a directory and mount the EFI System Partition:

    # cd /Volumes
    # mkdir efi
    # mount -t msdos /dev/disk0s1 /Volumes/efi

Then run bless on `grub.efi` and on the EFI partition to set them as the default boot options.

    # bless --folder=/Volumes/efi --file=/Volumes/efi/efi/arch_grub/grubx64.efi --setBoot
    # bless --mount=/Volumes/efi --file=/Volumes/efi/efi/arch_grub/grubx64.efi --setBoot

More info at https://help.ubuntu.com/community/UEFIBooting#Apple_Mac_EFI_systems_.28both_EFI_architecture.29.

Note: TODO: GRUB upstream Bazaar mactel branch http://bzr.savannah.gnu.org/lh/grub/branches/mactel/changes. No further update from grub developers.
Note: TODO: Experimental "bless" utility for Linux by Fedora developers - mactel-boot. Requires more testing.

## Asus

### Z68 Family and U47 Family

    # cp /boot/efi/EFI/arch_grub/grubx64.efi /boot/efi/shellx64.efi

After this launch the UEFI Shell from the UEFI setup/menu (in ASUS UEFI BIOS, switch to advanced mode, press Exit in the top right corner and choose "Launch EFI shell from filesystem device"). The GRUB2 menu will show up and you can boot into your system. Afterwards you can use efibootmgr to setup a menu entry, for example if you have the uefi partition in /dev/sda1: (read Unified_Extensible_Firmware_Interface)

    efibootmgr -c -g -d /dev/sda -p 1 -w -L "Arch Linux (GRUB)" -l /EFI/arch_grub/grubx64.efi

If your motherboard has no such option (or even if it does), you can use UEFI shell (Unified_Extensible_Firmware_Interface#UEFI_Shell) to create a UEFI boot option for the Arch partition temporarily.

Once you boot into the EFI shell, add a UEFI boot menu entry:

    Shell> bcfg boot add 0 fs1:\EFI\arch_grub\grubx64.efi "Arch Linux (GRUB2)"

where `fs1` is the mapping corresponding to the UEFI System Partition and `\EFI\arch_grub\grubx64.efi` is the the from the `--bootloader-id` from the `grub-install` command above.

This will temporarily add a UEFI boot option for the next boot to get into Arch. Once in Arch, modprobe `efivars` and confirm that `efibootmgr` creates no errors (no errors meaning you successfully booted in UEFI mode). Then Grub2#Install_to_UEFI_SYSTEM_PARTITION can be performed again and should successfully permanently add a boot entry in the UEFI menu.

### P8Z77 Family

- Boot to live media and chroot into the target system.
- Make sure that a 100 MB fat32 partition is marked as "EFI System" (gdisk terminology uses hex code ef00).

Note: If you get the message WARNING: Not enough clusters for a 32 bit FAT!, reduce cluster size with mkfs.vfat -s2 -F32 ... otherwise the partition may be unreadable by UEFI.

FROM WITHIN THE CHROOT

    # mount -t vfat /dev/sdXY /boot/efi
    # grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=arch --recheck
    # grub-mkconfig -o /boot/grub/grub.cfg
    # wget https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2/ShellBinPkg/UefiShell/X64/Shell.efi
    # umount /boot/efi

The EFI partition should be contain just two files:

    /Shell.efi
    /EFI/arch/grubx64.efi

- Reboot and enter the BIOS (the Delete key will do this).
- Using the arrow keys, move to the 'exit' menu and drop down to the EFI shell.
- Add an entry for Arch to the menu. Below is an example, see the UEFI#Launching UEFI Shell article for more.

FROM WITHIN THE EFI SHELL

    Shell> bcfg boot dump -v
    Shell> bcfg boot add 1 fs0:\EFI\arch\grubx64.efi "Arch Linux (grub manually added)"
    Shell> exit

- Reboot the machine and enter the BIOS.
- Navigate to the 'Boot' section and adjust the boot order to with the "Arch Linux (grub manually added)" being the one on the SSD.
- Boot to this entry and enjoy.

### M5A97

Finish the standard Arch install procedures, making sure that you install grub-efi-x86_64 and partition your boot hard disk as GPT.

From [1]:

The UEFI system partition will need to be mounted at `/boot/efi/` for the GRUB install script to detect it:

    # mkdir -p /boot/efi
    # mount -t vfat /dev/sdXY /boot/efi

Where X is your boot hard disk and Y is the efi partition you created earlier.

Install GRUB UEFI application to `/boot/efi/EFI/arch_grub` and its modules to `/boot/grub/x86_64-efi` using:

    # modprobe dm-mod
    # grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=arch_grub --recheck --debug
    # mkdir -p /boot/grub/locale
    # cp /usr/share/locale/en\@quot/LC_MESSAGES/grub.mo /boot/grub/locale/en.mo

Generate a configuration for GRUB

    # grub-mkconfig -o /boot/grub/grub.cfg

Then copy the modified UEFI Shell v2 binary UefiShellX64.efi into your ESP root.

    # cp ~/Shell2/UefiShellX64.efi /mnt/boot/efi/shellx64.efi

The reason that we need this shell application is that the efibootmgr command will fail silently during grub-install.

After this launch the UEFI Shell from the UEFI setup/menu (in ASUS UEFI BIOS, switch to advanced mode, press Exit in the top right corner and choose "Launch EFI shell from filesystem device"). The UEFI shell will show up. From here we need to add our GRUB UEFI app to the bootloader.

    Shell> bcfg boot add 3 fs0:\EFI\Arch_Grub\grubx64.efi "Arch_Grub"

where `fs0` is the mapping corresponding to the UEFI System Partition and `3` is the zero based boot entry index.

To list the current boot entries you can run:

    Shell> bcfg boot dump -v

## Intel

### S5400 Family

This board can run in BIOS or in EFI mode. BIOS mode requires an MBR-partitioned hard drive, EFI a GPT hard drive. Please note that this board operates on the Intel EFI v1.10 specification, and is i386 only. The normal procedure for UEFI installation can be followed, with the exception of the following changes.

- Instead of using the `grub-efi-x86_64` package, `grub-efi-i386` has to be used
- The `bcfg` command is not available for pre-UEFI (v2.0) firmware. A `startup.nsh` file can be used on the root of the EFI partition containing the path to the bootloader. For example:

`fs0:\EFI\arch_grub\boot.efi` has to be placed in the `startup.nsh` file on the root of the EFI partition.

- The `grub.cfg` file has to be placed in the same directory as the grub EFI file, otherwise grub will not find it and enter the interactive shell

Retrieved from "https://wiki.archlinux.org/index.php?title=GRUB_EFI_Examples&oldid=278238"
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