[[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.

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# fdisk -l
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== For Default Instalation in LVM.

. Create the mount point for the root partition.
+
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# mkdir -p /mnt/root
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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.
+
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# mount /dev/mapper/fedora-root /mnt/root
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. Mount the boot partition in the `boot` directory of the filesystem that you have mounted in the previous step.

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# mount /dev/sda1 /mnt/root/boot/
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== For default Instalation in BTRF

. Create the mount point for the root partition.

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# mkdir -p /mnt/
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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.

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# mount /dev/sda2 /mnt
# mount /dev/sda1 /mnt/root/boot
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IMPORTANT: Home Partition is mounted automatically under `/mnt/home`

== Continue with the follow Procedure.

. Mount system processes and devices into the root filesystem in 
`/mnt/root`.
+
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# 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
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. Change your filesystem into the one mounted under `/mnt/root`.
+
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# chroot /mnt/root
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. 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.
+
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$ exit
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. Your bootloader should be now restored. Reboot your computer to boot into your normal system.

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# systemctl reboot
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