E.3. Installing GRUB
In a vast majority of cases, GRUB is installed and configured by default during the installation of Red Hat Enterprise Linux. However, if for some reason GRUB is not installed, or if you need to install it again, it is possible to install grub manually.
On systems without UEFI firmware, a valid GRUB configuration file must be present at
/boot/grub/grub.conf. You can use the
grub-installscript (part of the grub package) to install GRUB. For example:
Replace disk with the device name of your system's boot drive such as
On systems with UEFI firmware, a valid GRUB configuration file must be present at
/boot/efi/EFI/redhat/grub.conf. An image of GRUB's first-stage boot loader is available on the EFI System Partitition in the directory
EFI/redhat/with the filename
grubx64.efi, and you can use the
efibootmgrcommand to install this image into your system's EFI System Partition. For example:
efibootmgr -c -d disk -p partition_number -l /EFI/redhat/grubx64.efi -L "grub_uefi"
Replace disk with the name of the device containing the EFI System Partition (such as
/dev/sda) and partition_number with the partition number of your EFI System Partition (the default value is 1, meaning the first partition on the disk).
The grub package does not automatically update the system boot loader when the package is updated using Yum or RPM. Therefore, updating the package will not automatically update the actual boot loader on your system. Use the
grub-installcommand manually every time after the package is updated.
For additional information about installing GRUB, see the GNU GRUB Manual and the
grub-install(8)man page. For information about the EFI System Partition, see Section 9.18.1, “Advanced Boot Loader Configuration”. For information about the
efibootmgrtool, see the