009.04.91.16. Could you explain the key techniques and commands used for troubleshooting GRUB2

pravjot

Ref: 08. 009.04.18.Troubleshooting with GRUB2

gaurav133232

Here is the explanation:-

Boot into Rescue or Single-User Mode

This mode is used to perform system repairs. This mode loads the minimum necessary services and allows root access for detailed troubleshooting.

Manual Boot from the GRUB command line

If the GRUB menu is corrupt or misconfigured, you can manually boot the system from the GRUB command line:

Use the 'ls' command to list all partitions and identify the linux system partition.
Set the root device with set root = '(hdX,Y)' where X and Y specify the hard disk and partition number.
Load the kernel with 'linux/vmlinuz' root = '/dev/sdXY ro' adjusting the path and partition as needed.
specify the initial ramdisk with 'initrd/initrd.img'.
Boot the system with 'boot' command.

Regenerating GRUB configuration

Corrupt or outdated GRUB configurations can cause boot issues. This can be resolved by regenerating GRUB file i.e grub.cfg .

Reinstalling GRUB2

In cases where GRUB2 is damaged -perhaps due to a failed update or disk error reinstalling grub2 can restore functionality.

The main precaution while resolving the issues is selecting the appropriate image, appropriate partition and the appropriate disk from which to boot.