This might or might not be a problem. But I can't enter to OpenFirmware. In order to get into OF usefully you may need either Apple's system disk utility or else the boot variables utility.
Some experimentation is likely to be needed.
There's a pretty long install document. Of course it may not be completely up to date. Make sure you check the FAQ as well. Unfortunately we don't have all the installation tools we want complete yet and some of the current procedure depends a lot on which exact revision of machine you are working on. If you want some more help please try to be a little more specific.