Just edit the configuration file for lilo as root
# [editor you use] /etc/lilo.conf
add the line
default = [label]
where [label] is the label attribute of the OS you would like to boot first.
Here's mine for guidance
Code:
boot = /dev/hda
prompt
timeout = 50
default = Win2000
vga = normal
image = /boot/vmlinuz-ide-2.4.26
root = /dev/hda5
label = Slack_2.4.26
read-only # Non-UMSDOS filesystems should be mounted read-only for checking
image = /boot/vmlinuz
root = /dev/hda5
label = Slack_2.6.15.6
read-only
other = /dev/hda1
label = Win2000
table = /dev/hda
You're on your own for the editor to use. nano or pico are good console editors as is vim (a little more advanced).
IMPORTANT: Always run
# lilo
after editing lilo.conf
Cheers