Reinstall a corrupted boot partition.

 Issue

In a system where the "/boot" partition is a separate partition, when /boot is corrupted or be
formatted mistakenly, you can not boot the system but do not want to reinstall the whole
system.

Environment
• Red Hat Enterprise Linux, CentOS, Fedora/
• /boot partition is installed on the first partition of your first disk
• x86 architecture

Resolution

Reinstall /boot partition manually with the following steps:

1. Boot the system into rescue mode with the help of CD or DVD:
   At boot prompt, type "linux rescue".
This will start the rescue mode program.
You will be prompted for your keyboard and language requirements.
Enter these values as
you would during the installation of Red Hat Enterprise Linux.
Next, a screen will appear telling you that the program will now attempt to find a Red Hat
Enterprise Linux installation to rescue. Select "Continue" on this screen.

2. At the "sh-3.1" prompt, chroot to /mnt/sysimage:
# chroot /mnt/sysimage

3. Make sure the boot partition is labeled as described in /etc/fstab. (Assuming the boot partition is /dev/sda1):
# e2label /dev/sda1 /boot

4. Make sure the boot partition is mounted:
# mount /dev/sda1 /boot

5. Mount the CD to install the following rpms:
# mkdir /mnt/iso
# mount -o loop,ro /dev/hdc /mnt/iso
# cd /mnt/iso/Server
# rpm -Uvh --replacefiles --replacepkgs grub-0.97-13.i386.rpm
# rpm -Uvh --replacefiles --replacepkgs redhat-logos-4.9.16-1.noarch.rpm
# rpm -ivh --replacefiles --replacepkgs kernel-2.6.18-8.el5.i686.rpm

6. Install the GRUB:
# grub-install /dev/sda

7. If /boot/grub/grub.conf is lost, you need to create it manually. The following is a sample of
grub.conf, please make sure the the file "vmlinuz-2.6.18-8.el5" and "initrd-2.6.18-8.el5.img"
exist under the directory of /boot (which should be installed after step 4).

8. default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux (2.6.18-8.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-8.el5 ro root=LABEL=/
initrd /initrd-2.6.18-8.el5.img

9. Make a soft link to grub.conf:
# cd /boot/grub
# ln -s grub.conf menu.lst
Then reboot the system.