Thanks for praising my Grammar, though I doubt I deserve it.
However, BootPROM or to be exact the "OpenBoot PROM" is part of the Sparc Hardware Architecture. It is there from the very beginning, that is even if you never ever had installed Solaris before on this machine. Also even if you install Solaris on a x86 system, you will still not have a BootPROM there. So the BootPROM is indeed NOT a part of the Solaris package. (quoting from
Administering the Boot PROM : "OpenBoot is independent of the Solaris operating environment; output normally goes to the system console. The monitor is under the control of OpenBoot rather than the operating system because there might not be any operating system running yet.")
But the Solaris OS provides a few commands/tools to access the NVRAM from within a shell, and therefore allows you to administer the OpenBoot PROM by other means than the OpenBoot Prompt (aka "ok prompt"), which can be reached by STOP-A on a Sun Keyboard or through a Break signal, if connected to the primary terminal. And although you can resume OS operation after these key sequences by running the OpenBoot command "go", it is considered an unsafe operation and you are expected to reboot your system immediately after resuming. Therefore the Solaris provided utilities are the only safe way to alter the OpenBoot PROM without the need to immediately reboot your system, though this may still be required to activate your changes.
And yes, I have good knowledge of Sun hardware and the Solaris OS. I operated them for a living for several years, starting with SS5 and up to E10K/E15K and from Solaris 2.1 to 9 respectively.
cu