[[restoring-bootloader-using-live-disk]] = Restoring the bootloader using the Live disk. Sometimes, especially after a secondary operating systems has been installed, the master boot record gets damaged which then prevents the original Linux system from booting. If this happens, it is necessary to reinstall *GRUB2* to recreate the original settings. The process not only discovers all installed operating systems, but usually adds them to the *GRUB2* configuration files, so they will all become bootable by *GRUB2*. .Before you start * Get the Fedora Live ISO from link:https://download.fedoraproject.org/pub/fedora/linux/releases/[getfedora.org]. * Prepare a bootable device using the downloaded ISO, either a CD or a USB. .Procedure . Boot the Fedora live system from the bootable device you have created. . Open the terminal. . Examine the partition layout and identify the `boot` and the `root` partition. ---- sudo fdisk -l ---- == For Default Instalation in LVM. . Create the mount point for the root partition. + ---- mkdir -p /mnt/root ---- If you are using the default Fedora layout, there will be one `/dev/sda1` partition that holds the `/boot` directory and one `/dev/mapper/fedora-root` that holds the root file system. . Mount the root partition on the mount point. + ---- mount /dev/mapper/fedora-root /mnt/root ---- . Mount the boot partition in the `boot` directory of the filesystem that you have mounted in the previous step. + ---- mount /dev/sda1 /mnt/root/boot/ ---- . Mount system processes and devices into the root filesystem in `/mnt/root`. + ---- mount -o bind /dev /mnt/root/dev mount -o bind /proc /mnt/root/proc mount -o bind /sys /mnt/root/sys mount -o bind /run /mnt/root/run ---- . If you use EFI boot, you may also want to bind the efivars and the EFI system partition: + ---- mount -o bind /sys/firmware/efi/efivars /mnt/root/sys/firmware/efi/efivars mount /mnt/root/boot/efi ---- . Change your filesystem into the one mounted under `/mnt/root`. + ---- chroot /mnt/root ---- == For default Instalation in BTRF . Create the mount point for the root partition. + ---- mkdir -p /mnt/ ---- If you are using the default Fedora layout, there will be one `/dev/sda1` partition that holds the `/boot` directory and one `/dev/sda2` that holds the root file system. ---- mount /dev/sda2 /mnt mount /dev/sda1 /mnt/root/boot ---- . Change your filesystem into the one mounted under `/mnt/root`. + ---- chroot /mnt/root ---- IMPORTANT: Home Partition is mounted automatically under `/mnt/home` == For Default Instalation in LUKS. . Make sure crypt module in use: + ---- sudo modprobe dm-crypt ---- . Find out which drive it was with the following command: + ---- sudo fdisk -l ---- You must mount `/dev/sda3 myvolume` . Use `cryptsetup`, device is accessible under `/dev/mapper/myvolume`` + ---- sudo cryptsetup luksOpen /dev/sde3 myvolume ---- . Scan for LVM volumes and choose the right volume group name that you are looking for: + ---- sudo vgscan ---- . If it is eg. Fedora, activate it + ---- sudo vgchange -ay system ---- . Find out root volume + ---- sudo lvs ---- . Mount it with the following command: + ---- sudo mount /dev/system/root /mnt/ ---- . To work in the volume use the following commands + ---- sudo mount --bind /dev /mnt/dev sudo mount --bind /dev/pts /mnt/dev/pts sudo mount --bind /proc /mnt/proc sudo mount --bind /sys /mnt/sys sudo chroot /mnt ---- IMPORTANT: consider mounting `/boot` also. == Continue with the follow Procedure. . Regenerate the *GRUB2* configuration file and reinstall the bootloader into the MBR, as described in xref:adding-other-operating-systems-grub2[Adding other operating systems to the *GRUB2* menu]. . Exit this temporary root filesystem. + ---- exit ---- . Your bootloader should be now restored. Reboot your computer to boot into your normal system. ---- systemctl reboot ----