The boot PROM is used to boot a system. You might need to change the way the system boots. For example, you might want to reset the device to boot from or run hardware diagnostics before you bring the system to a multiuser level.
System administrators typically use the PROM level to boot a system. You can also change the default boot file and boot device at the PROM level.
If you need to perform any of the following tasks, you need to change the default boot device:
Add a new drive to the system either permanently or temporarily
Change the network boot strategy
Temporarily boot a stand-alone system from the network