There's this hint:
http://www.macosxhints.com/article.php?story=20060301112336384
But you'll need a keyboard. Even if you unplug the motherboard IDE, Open Firmware doesn't search the USB bus for volumes when it tries to boot, so you'll just have to borrow a USB keyboard or take the drive out of the USB enclosure.
http://www.macosxhints.com/article.php?story=20060301112336384
But you'll need a keyboard. Even if you unplug the motherboard IDE, Open Firmware doesn't search the USB bus for volumes when it tries to boot, so you'll just have to borrow a USB keyboard or take the drive out of the USB enclosure.