quick-docs/en-US/modules/proc_restoring-bootloader-using-live-disk.adoc
Lukas Ruzicka 886b12ffd2 Update grub2.adoc
* Edit original content
* Add new content
* Fix asciidoc markup
* Modularize
2017-12-14 09:44:46 +01:00

72 lines
2.3 KiB
Text

= Restoring the bootloader using the Live disk.
[[restoring-bootloader-using-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/27/Workstation/x86_64/iso/Fedora-Workstation-Live-x86_64-27-1.6.iso[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
----
+
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.
. Create the mount point for the root partition.
+
----
$ sudo mkdir -p /mnt/root
----
. Mount the root partition on the mount point.
+
----
$ sudo 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.
+
----
$ sudo mount /dev/sda1 /mnt/root/boot/
----
. Mount system processes and devices into the root filesystem in `/mnt/root`.
+
----
$ sudo mount -o bind /dev /mnt/root/dev
$ sudo mount -o bind /proc /mnt/root/proc
$ sudo mount -o bind /sys /mnt/root/sys
$ sudo mount -o bind /run /mnt/root/run
----
. Change your filesystem into the one mounted under `/mnt/root`.
+
----
$ sudo chroot /mnt/root
----
. 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.
+
----
$ sudo systemctl reboot
----