Restore the Linux bootloader in Rescue
The main boot loader for Linux operating systems is GRUB. If you have problems, you can recover the bootloader using the LiveCD — boot to Rescue.
In the Live system, mount all partitions to a pre-created folder (e.g. /mnt
) in the same way as they were mounted in the main system.
To restore the bootloader:
-
Start the system from the LiveCD and open the terminal.
-
Locate the root partition where the system is installed using the
fdisk
command (find the partition with theLinux filesystem
type in the output):fdisk -l
If the system is installed in a non-LVM partition, the root partition will be in
/dev/sda*
:- in a partition using LVM —
/dev/mapper
; - if partitions are on a software RAID array —
/dev/md*
(mounting is performed to the corresponding array);
- in a partition using LVM —
-
Suppose the main system has a root partition
/
located in/dev/sda2
and a/boot
partition located in/dev/sda1
. Mount the partitions in/mnt
:mount /dev/sda2 /mnt/
mount /dev/sda1 /mnt/bootIf you are using a UEFI bootloader, mount the EFI partition as well:
mount /dev/sda3 /mnt/boot/efi
Specify
/dev/sda3
as the c EFI partition.Use the
cat /mnt/etc/fstab
command to see the mount point in the host OS, as well as the UUID of the disk and map it to the UUID of the disk in the Live image. -
Mount the
/sys
,/proc
,/dev
directories:mount --bind /sys /mnt/sys
mount --bind /proc /mnt/proc
mount --bind /dev /mnt/dev -
Navigate to the main system environment using
chroot
:chroot /mnt
If an error occurs, use the command with
/bin/bash
:chroot /mnt /bin/bash
-
If GRUB is not installed on the disks, install it. If no installation is required, skip to step 7. GRUB must be installed on all disks from which you plan to boot. For example, if RAID0 is used for the boot partition:
grub-install /dev/sda
grub-install /dev/sdbDepending on the number of devices, there may be more disks in the RAID.
-
To generate a GRUB configuration file, type:
update-grub
or
update-grub2
-
Exit the
chroot
environment:exit