Installing onto PowerCenter 120

[The Nose Who Knows <bignose@zip.com.au>]

Howdy all,

I've been fighting for a few months now to get Debian PowerPC (Potato)
onto a donated PowerComputing PowerCenter 120.

I've managed to have the install disks boot and run all the way through
the install menus, putting the system on the hard drive.  However, on
reboot the system won't boot up to Debian, giving only the
"questionmark-mac" display, which I presume means it doesn't know what
it should be booting.

Many references I've read talk about changing OpenFirmware settings, but
I am unable to access the OpenFirmware -- hotkey sequences have resulted
in either no effect, or a black screen, and the Debian rescue disk
doesn't give me anything in /proc/devicetree (I think that was the
path), which surprised some people I spoke to on #debian.

Others have told me I need to fool around in MacOS, but that no longer
exists on this machine; and I'd like to be proud of the fact that I can
use the machine with Debian alone, if possible.

Any pointers, or requests for more info, would be appreciated.

 \
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_o__) BIGNOSE