Change your bootlist so that cd0 appears before your bootable disks.
Example:
bootlist -m normal cd0 hdisk0 hdisk1
bootlist -m service cd0 rmt0 hdisk0 hdisk1

Setting the normal and service mode bootlists as shown above will result in
the system checking the cdrom drive first for a bootable cd, then trying the
next device in the series if it doesn't find a bootable cd.
George Hays
Unix Systems Administrator
EDS
(916)859-6901
george.hays AT eds DOT com