Now that you know the LIF area will do its part, you need to find out what hardware paths the system will use. The primary boot path should probably be the primary boot disk in your root volume group. The alternate boot path should be checked for a valid path in your environment. One other item that the system will use during boot is the AUTO file. Once on the file system, you can inspect the contents.
Many environments have identical hpux commands on both the primary and mirror boot disks.
You may want to reconsider. I like to have the primary disk boot normally and the mirror disk boot with the flag set to override LVM quorum. If you are booting to the mirror, you have probably lost your primary boot disk. If you have just two disks in the root volume group, you will not meet the LVM requirement of 50 percent disk availability. With luck, you will not have to inspect your systems for a bootable configuration every day, or even much more than occasionally.