- reboot zapping the PRAM and the press option-command-o-f to boot into the OF, if it doesn't work try again, you want the OF settings before MacOS touches them
Carful! This is likely not to work if your box defaults it's input- and output-device to ttya. You'll need a two box setup to get the "original" nvram default settings. But then again you may not need them... you need the ones that work ;)
Christian Funk