44.6. Verifying the Boot Loader

The kernel RPM package configures the boot loader to boot the newly installed kernel (except for IBM eServer iSeries systems). However, it does not configure the boot loader to boot the new kernel by default.
It is always a good idea to confirm that the boot loader has been configured correctly. This is a crucial step. If the boot loader is configured incorrectly, the system will not boot into Red Hat Enterprise Linux properly. If this happens, boot the system with the boot media created earlier and try configuring the boot loader again.

44.6.1. x86 Systems

All x86 systems (including all AMD64 systems) use GRUB as the boot loader. GRUB

Confirm that the file /boot/grub/grub.conf contains a title section with the same version as the kernel package just installed
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/hda2
#          initrd /initrd-version.img
default=1 timeout=10
title Red Hat Enterprise Linux (2.6.9-5.EL)
         root (hd0,0)
	 kernel /vmlinuz-2.6.9-5.EL ro root=LABEL=/
	 initrd /initrd-2.6.9-5.EL.img
title Red Hat Enterprise Linux (2.6.9-1.906_EL)
         root (hd0,0)
	 kernel /vmlinuz-2.6.9-1.906_EL ro root=LABEL=/
	 initrd /initrd-2.6.9-1.906_EL.img
If a separate /boot/ partition was created, the paths to the kernel and initrd image are relative to /boot/.
Notice that the default is not set to the new kernel. To configure GRUB to boot the new kernel by default, change the value of the default variable to the title section number for the title section that contains the new kernel. The count starts with 0. For example, if the new kernel is the first title section, set default to 0.
Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly.