RHEL: Reinstalling Boot Loader on the Master Boot Record (MBR)

# Tested on RHEL 5 & 6

# In many cases, the GRUB boot loader can mistakenly be deleted, corrupted or replaced.
# We can manually reinstall GRUB on the master boot record, using either "grub-install"
# or the "grub" prompt.

# Ensure the device.map file located in the /boot/grub directory lists all boot devices
# in the same order detected by system ROM.

# grub-install -----------------------------------------------------------------------------

cat device.map
   # this device map was generated by anaconda
   (hd0)     /dev/cciss/c0d0

# Use the 'grub-install' command pointing to the root device.

grub-install /dev/cciss/c0d0


#  --- OR ---


# "grub" utility ---------------------------------------------------------------------------

# Manually set up the MBR and /boot partition from the grub prompt. (hd0) and (hd0,0) should
# coincide with the results from the "find" command. It may be that "find" command will
# fail showing an error message; if that's the case we can continue with the procedure as
# "find" step is not mandatory

grub
   grub> find /boot/grub/stage1
   grub> root (hd0,0)
   grub> setup (hd0)

# ------------------------------------------------------------------------------------------


# If a crash occurred on the server and GRUB boot loader was lost, this may be recovered by
# booting from a rescue CD.

# After the command prompt is displayed, change the root directory to the OS installation
# by typing this command:

chroot </mnt/sysimage>

# Review the /boot/grub/grub.conf file, as additional entries may be needed for GRUB to control
# additional operating systems.

0 (0)
Article Rating (No Votes)
Rate this article
Attachments
There are no attachments for this article.
Comments
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
Build a simple RPM that packages a single file
Viewed 8734 times since Sat, Jun 2, 2018
OEL 7 – How to disable IPv6 on Oracle Linux 7 – Follow Up
Viewed 9625 times since Wed, Jul 25, 2018
RHEL7: How to get started with Firewalld.
Viewed 12257 times since Wed, May 22, 2019
Linux - How to monitor CPU usage
Viewed 6602 times since Fri, Jun 8, 2018
How to automate SSH login with password? ssh autologin
Viewed 2870 times since Fri, Jun 8, 2018
LVM: Mount LVM Partition(s) in Rescue Mode
Viewed 5022 times since Sat, Jun 2, 2018
How To Find Largest Top 10 Files and Directories On Linux / UNIX / BSD find
Viewed 4004 times since Mon, Oct 29, 2018
10 Linux rsync Examples to Exclude Files/Directories
Viewed 11087 times since Wed, Oct 31, 2018
Moving SSL Certificate from IIS to Apache
Viewed 2131 times since Mon, Feb 18, 2019
HowTo: Kill TCP Connections in CLOSE_WAIT State
Viewed 16165 times since Thu, Feb 14, 2019