For further reference

The Solaris 2 OpenBoot Command Reference Manual will provide a great deal of information about the PROM setup and available commands. The PROM includes a FORTH language interpreter, so there are a large number of sophisticated operations you can do with it, including defining your own command set. To some extent you can debug with it just as with adb or kadb , including setting breakpoints and examining memory. It is less user friendly in that the symbols are not available, but for those emergency situations where you don't have kadb loaded, the PROM can allow you to examine and modify the kernel, the machine state, and even devices.