This guide contains useful information to access a damaged linux installation. To proceed you need to get the live Condres OS.
Start the compunter with the live
Check the name of the partition that contains the installation with the command
fdisk -l
mount the installation partition in the / mnt directory, for example /dev/sda2
sudo su
mount /dev/sda2 /mnt
if the /boot or /var (or any other) folders are in a separate partition, you need to mount them inside the /mnt, example:
mount /dev/sda3 /mnt/var
mount /dev/sda1 /mnt/boot
Mount the rest of the devices with the controls:
mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
Run the chroot command specifying the destination folder and shell to use
chroot /mnt /bin/bash
For BIOS Systems
1. Install a new GRUB bootloader with the following command:
grub-mkconfig -o /boot/grub/grub.cfg
grub-install /dev/sda
2. Recheck to ensure the that installation has completed without any errors:
grub-install --recheck /dev/sda
3. Finally, configure the freshly installed GRUB bootloader:
update-grub
All done! Now close the terminal and reboot your system to use your freshly re-installed GRUB.
Warning: this procedure can cause a chroot error
1.) First of all check the partition for the ESP (EFI System Partition). An ESP is a fat32 partition and contains .efi files for booting.
It can be checked using Gparted or from the terminal using fdisk -l
(Note: If you do not have a EFI partition, you will need to create it. Use Gparted for that.
Type- fat32
Size- 512 mb to 1 gb)
2.) Create the /boot/efi directory
sudo mkdir /boot/efi
3.) Mount the EFI partition as /boot/efi
sudo mount /dev/sdXY /boot/efi
X = Alphabet of the drive = a,b,c … Y = Partition number of the EFI partition = 1,2,3,4…
Example – /dev/sda4
4.) Re-install Grub.
sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=condres --recheck
5.) Update Grub configuration file.
sudo update-grub
Note
If you get something like
EFI variables are not supported on this system.
Then install the efibootmgr, dosfstools and grub packages and try steps 4 and 5 again.
If it still doesn’t work, then try exiting the chroot environnment by typing exit, then loading the efivarfs module:
sudo modprobe efivarfs
and in the chroot
mount -t efivarfs efivarfs /sys/firmware/efi/efivars
And if you get something like
grub-install: error: failed to get canonical path of `union'.
