ROM's gone long time now
Macs no longer have a big chunk of core capability burned into roms. It was making virtual memory management a pain so they simplified and chucked them.
OTOH, there's quite likely to be some built-in hardware dongly thing that the OS looks for or dies.
"Whenever you find you are on the side of the majority, it is time to pause and reflect" --Mark Twain
"The significant problems we face cannot be solved at the same level of thinking we were at when we created them." --Albert Einstein
"This is still a dangerous world. It's a world of madmen and uncertainty and potential mental losses." --George W. Bush