AN05: How to salvage a Linux by Super Grub2 Disk
In case the GRUB is broken in a system, the system is unable to boot. Unfortunately, the LiveCD doesn't have the grub. So, it is not helpful.
The Super Grub2 Disk is a very strong ISO image that can salvage your system easily, even if it is fully encrypted. You can recover your system easily by using this menu-driven software.
The following sequence will overwrite the Windows boot loader. Make sure you did back up the BitLocker recovery key. And then suspend the BitLocker before the following tasks, to prevent the Windows prompts to input the BitLocker recovery key.
First of all, download an image of the Super Grub2 Disk from the official site. And then, create a bootable media of the Super Grub2 Disk.
Let's start with the easiest way. If you are lucky, there are still GRUB programs that exist in the EFI partition, and you can boot your system from that data.
Start your system with the Super Grub2 Disk. You will see a GRUB menu like below. To try the easy recovery, select the "Detect and show boot methods" and type the ENTER key.
Then, GRUB will show you the possible resources you can you. Choose the most preferable menu and type the ENTER key. For your information, the GRUB program is stored in the /efi/ubuntu directory. In the example below, (hd1,gpt1)/efi/ubuntu/grubx64.ef seems to be the correct one.
If the choice is correct and still program/data are alive, GRUB runs boot sequence and asks you to type the passphrase. After typing correctly, you will see your system start as normal.
Once your system is booted, make sure to re-install the GRUB to fix the problem.
sudo grub-installIf you are unlucky or using BIOS system, Super Grub2 Disk might not find the easy way to boot. In this case, you need to boot from the encrypted root.
To enable the volume decrypting, select the "Extra GRUB2 functionality..." and type the ENTER key.
And then, select the "Mount encrypted volumes (LUKS and geli)" and type ENTER key.
Now, GRUB searches for the encrypted partition and asks to type the passphrase to open. After typing the correct passphrase, GURB returns to the menu automatically by 5 seconds.
Then, enable the LVM.
Now, the encrypted partition is decrypted, and LVM logical volumes are mounted. We can try the "Detect and show boot methods" again.
By scrolling, you will see the list of your GRUB menu. Choose the appropriate one and type ENTER key. You will see your system starts.
Once your system is booted, make sure to re-install the GRUB to fix the problem.
sudo grub-installThe Super Grub2 disc is a strong and easy tool to salvage your Linux system when the GRUB is broken.
On the other hand, restoring your Linux GRUB may change the Windows boot loader and let it ask you the BitLocker recovery key. To be sure to backup your data and recovery key. Also, suspend the BitLocker protection before fixing your GRUB. After you fix the GRUB, you can resume the BitLocker again.