How to reinstall GRUB and GRUB2 on UEFI-based machines?

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 9
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 6

Issue

  • The host does not boot into the GRUB menu.
  • The motherboard was replaced and is now not booting to GRUB.
  • /boot/efi/EFI/redhat/grub.cfg was deleted or corrupted

Resolution

Red Hat Enterprise Linux 7 and above

  • Run the below commands to reinstall the various packages need for booting uefi, this will reinstall all of the files under /boot/efi/EFI/.

    # yum reinstall grub2-efi-x64 shim-x64
or
# rpm -ivh --replacepkgs --replacefiles grub2-efi-x64-<version>.rpm shim-x64-<version>.rpm
Additional step for RHEL 9 and later

To recover a deleted /boot/efi/EFI/redhat/grub.cfg, it's required to reinstall grub2-common which triggers a scriptlet that generates /boot/efi/EFI/redhat/grub.cfg.

# yum reinstall grub2-common

  • After the packages above have been successfully reinstalled, it may be necessary to add a new uefi boot entry for example, if the motherboard was replaced then replace the disk part shown in the below command with the disk that /boot/efi is located.
    Warning: If the system is currently booted from a different system than what the OS disks normally use (for example, if the disks have been attached to a rescue virtual machine), do not run the efibootmgr command. This command updates the NVRAM on the motherboard; running it from a different system will update the NVRAM of the currently booted environment, which can leave that system in a broken state. For any questions or concerns, please open a new or update an existing Red Hat Support Case.

    # efibootmgr -c -d /dev/<disk> -p 1  -l \\EFI\\redhat\\shimx64.efi -L "Red Hat Enterprise Linux <insert  7 or 8 or 9 or 10 here depending on system version>"

If issue still remains

  • Check if the new boot entry is added properly, by running the below command.

    # efibootmgr -v

  • If the entry is added correctly, please create a case with support and include the output of the above command.

Red Hat Enterprise Linux 6

  • Run the below commands to reinstall the grub package, this will reinstall the /boot/efi/EFI/redhat/grub.efi file in case it is corrupt or removed.

    # yum reinstall grub
or
# rpm -ivh --replacepkgs --replacefiles grub-<version>.rpm

  • After the grub package has been successfully reinstalled, it may be necessary to add a new UEFI boot entry, for example, if the motherboard was replaced. Replace the disk portion shown in the command below with the disk where /boot/efi is located (e.g., sda).
    Warning: If the system is currently booted from a different system than what the OS disks normally use (for example, if the disks have been attached to a rescue virtual machine), do not run the efibootmgr command. This command updates the NVRAM on the motherboard; running it from a different system will update the NVRAM of the currently booted environment, which can leave that system in a broken state. For any questions or concerns, please open a new or update an existing Red Hat Support Case.

    # efibootmgr -c -d /dev/<disk> -p 1  -l \\EFI\\redhat\\grub.efi -L "Red Hat Enterprise Linux 6"

Root Cause

  • Common reasons for needing to reinstall GRUB for uefi installs:
    • motherboard replacement
    • The /boot/efi directory being wiped or corrupted
    • The wrong uuid is included in /boot/efi/EFI/redhat/grub.cfg
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