Can't Turn off firmware password
what if your screen is broken and you cannot turn it off?
MacBook
You can boot the Mac in clamshell mode. Connect it to power, attach an external display (can be a TV, you may need an adapter), and attach an external keyboard and mouse (USB in this case, since it will be hard to pair a new Bluetooth device), boot the Mac (into recovery mode, for this), then immediately close the lid.