Quick guide to recover a corrupt GRUB bootloader in Linux

🚀 Cómo solucionar el error paso a paso

Paso 1: Iniciar desde una distribución Live USB y localizar particiones

Insert a Live USB compatible with your current distribution, boot it in UEFI/BIOS mode, and detect your hard drive identifier:

sudo fdisk -l

(Identify your Linux root partition, for example /dev/sda2, and the EFI partition in FAT32 format, for example /dev/sda1).

Paso 2: Montar el sistema dañado y preparar el chroot

Mount the directory structure of the damaged file system in the temporary session:

# Montar partición raíz
sudo mount /dev/sda2 /mnt

# Montar directorios de comunicación del kernel
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done

# Montar partición EFI si usas UEFI
sudo mount /dev/sda1 /mnt/boot/efi

Paso 3: Entrar al sistema (chroot) y reinstalar GRUB

Log in as a superuser into your original file system environment and reinstall the bootloader:

# Cambiar la raíz del shell
sudo chroot /mnt /bin/bash

# Reinstalar GRUB apuntando al disco (reemplazar /dev/sda por el disco físico general)
grub-install /dev/sda

# Regenerar el archivo de configuración del menú de arranque
update-grub

# Salir y desmontar
exit
sudo reboot

🛡️ Consejo de Prevención

Recommended security practices:

• Before modifying the partition order or installing major kernel updates, generate backups of the GRUB configuration (/etc/default/grub). Never manipulate or force GRUB installation on the EFI partition (grub-install /dev/sda1) instead of the physical disk device (/dev/sda), as this can permanently corrupt your motherboard's EFI mount tables, preventing it from recognizing any storage media during the power-on self-test (POST).