36.6.3. IBM S/390 and IBM eServer zSeries Systems

The IBM S/390 and IBM eServer zSeries systems use z/IPL as the boot loader, which uses /etc/zipl.conf as the configuration file. Confirm that the file contains a section with the same version as the kernel package just installed:
[defaultboot]
default=old
target=/boot/
[linux]
        image=/boot/vmlinuz-2.6.9-5.EL
        ramdisk=/boot/initrd-2.6.9-5.EL.img
        parameters="root=LABEL=/"
[old]
        image=/boot/vmlinuz-2.6.9-1.906_EL
        ramdisk=/boot/initrd-2.6.9-1.906_EL.img
        parameters="root=LABEL=/"
Notice that the default is not set to the new kernel. To configure z/IPL to boot the new kernel by default change the value of the default variable to the name of the section that contains the new kernel. The first line of each section contains the name in brackets.
After modifying the configuration file, run the following command as root to enable the changes:
/sbin/zipl
Begin testing the new kernel by rebooting the computer and watching the messages to ensure that the hardware is detected properly.