The Error
While trying to boot grub2 shows:
error: can't find command 'ffffffffff.....
and the system is unable to boot.
The Solution
It is possible that the grub2 modules in
/boot/grub2/fonts/ /boot/grub2/i386-pc/ /boot/grub2/locale/
have become corrupted.
To remedy any bootloader corruption, boot the server into rescue mode and reinstall the grub2 package:
1. Boot the VM from the install ISO image and enter rescue mode ( Troubleshooting -> Rescue a linux system ).
2. Do not allow rescue mode to mount the root filesystem.
3. Activate any LVM devices.
# lvm pvscan # lvm vgscan # lvm lvscan # vgchange -ay
The LVM devices should appear in the /dev/mapper directory.
4. Mount the devices to make their content accessible.
# mount /dev/mapper/xxxx-root-lvm-xxx /mnt/sysimage # mount /dev/mapper/xxxx-var-lvm-xxx /mnt/sysimage/var # mount /dev/mapper/xxxx-usr-lvm-xxx /mnt/sysimage/usr
include procfs, sysfs, dev via a bind mount.
# mount /proc /mnt/sysimage/proc/ -o bind # mount /dev /mnt/sysimage/dev/ -o bind # mount /sys /mnt/sysimage/sys/ -o bind
and mount the boot partition:
# mount /dev/xvda1 /mnt/sysimage/boot
5. Make the newly-mounted partitions the current working context.
# chroot /mnt/sysimage
6. Enable the network so the grub2-tools TPM can be re-installed via yum(8) if not already installed.
# ifup eth0
7. Re-install the grub2-tools RPM package.
# yum reinstall grub2-tools
8. Re-install grub2:
# grub2-install /dev/xvda
9. And then reboot:
# echo Exit from chroot shell # exit # echo Exit from rescue shell to reboot # exit