GRUB

GRUB is a popular bootloader used by linux users.

Repairing/Reinstalling GRUB

When dual-booting Windows, GRUB can break if you:

• install a new Windows update
• reinstall Windows

Plus, it's just very easy to break.

Before reinstalling GRUB, confirm that the error is not repairable with any of these fixes.

I have found that the most optimal way of reinstalling GRUB is to use live installation media and chrooting.

1. Prepare a bootable USB
2. Check partition layout using lsblk

3. Mount partitions

   Note

   If you're using btrfs subvolumes, you need to mount them separately, then mount the boot partition. For example:

   mount -o subvol=@ /dev/nvme0n1p2 /mnt
   mount -o subvol=@home /dev/nvme0np2 /mnt/home
   mount /dev/nvme0n1p1 /boot
   

   Warning

   Your esp (the mount of of your ESP) might be set to /boot/efi, in which case, you should mount the boot partition at its repective location.

4. chroot

   chroot /mnt
   

   Note

   If you're using Arch Linux, arch-chroot is also available

   Consult the arch wiki for additional information.

5. Ensure that the kernel images exist