How do I reinstall GRUB from a Live USB?

Boot Live USB, mount root: mount /dev/sdXY /mnt, then: grub-install --root-directory=/mnt /dev/sdX, and: chroot /mnt update-grub.

Why did Windows overwrite GRUB?

Windows updates sometimes overwrite the EFI boot entry. Fix: boot Linux via USB, reinstall GRUB, or use efibootmgr to restore the boot entry.

Linux GRUB Rescue — Minimal BASH-like Error & Boot Recovery

Criticalboot

Overview

Fix GRUB rescue 'error: no such partition' and 'minimal BASH-like line editing' prompt caused by partition changes, deleted Linux partitions, or corrupted GRUB installation.

Key Details

GRUB rescue mode appears when GRUB cannot find its configuration or modules
'error: no such partition' means the partition GRUB was installed from has been moved or deleted
GRUB needs to know: (1) where its modules are, (2) where Linux kernel is, (3) the root filesystem
Common after resizing partitions, dual-boot changes, or Windows reinstallation
GRUB rescue provides limited commands: ls, set, insmod, linux, initrd, boot

Common Causes

Partition table changed (resized, deleted, reordered) after GRUB installation
Windows Boot Manager overwriting GRUB in the EFI partition
Deleted Linux partition while GRUB still references it
GRUB config (grub.cfg) corrupted or missing
UUID of the boot partition changed after formatting

Steps

1In GRUB rescue, list partitions: ls — note partitions like (hd0,msdos1) or (hd0,gpt2)
2Find the partition with GRUB: ls (hd0,gptN)/boot/grub — look for the one that does not error
3Set root and prefix: set root=(hd0,gptN) and set prefix=(hd0,gptN)/boot/grub
4Load normal module: insmod normal then normal — this should boot to full GRUB menu
5After booting: run sudo update-grub and sudo grub-install /dev/sdX to permanently fix