Quote Originally Posted by Rive
image=/mnt/hda2/vmlinuz-2.4.20-8
label="RedHat"
initrd=/mnt/hda2/initrd-2.4.20-8
read-only
This should work indeed provided you've mounted your RedHat partition before trying to run lilo: "mount /mnt/hda2"

Also if your RedHat kernel needs some startup parameters (check /mnt/hda2/boot/grub/menu.lst), make sure to include them in lilo.conf as well.