Here's a thought. First some background:
Last night, just to prove it could be done, I succeeded (first try)
in using BootX under MacOS9 on an OldWorld PowerMac G3 (beige
mini-tower) to load and run the debian-installer kernel and initrd
downloaded from:
<http://ftp.debian.org/dists/sarge/main/installer-
powerpc/beta3/images/powerpc/netboot/>
I got as far as the point where the d-i tries to install a
bootloader. It died there because there is no boot loader for the
oldworld subarchitecture.
I could have done the same thing using miboot, but it would have
been *much* harder. BootX has a nice Mac-like user friendly
interface. Miboot most definitely does not.
The amount of MacOS actually needed for this is quite small. With
a little work, I've gotten the corresponding thing for yellowdog
Linux down to under 50 MB and put it on a zip disk.
So here's my suggestion:
Declare that all OldWorld machines must have a minimal MacOS
partition with BootX as their "boot loader". That is, If you want
to use debian-sarge on an OldWorld Mac, it presupposes that you
first have MacOS and BootX installed on that machine.
Do not provide BootX on the CD, just a note in the README document
that says you need it and how to download it from, say, "non-free"
or "contrib".
Now the part of debian-installer that died on me last night has an
easy fix: Simply do not install any boot loader at all for that
subarchitecture.
This makes installing a new kernel on an oldworld machine a bit
tedious because you have to manually copy the new kernel binary and
any associated initrd to the right places on your MacOS partition,
and make manual changes to the parameters on BootX. Also, since
HFS+ filesystem support is still iffy enough that it's recommended
to use it read-only, this means that your MacOS partition should be
HFS rather than HFS+. Some folks may find that irksome, but it's
definitely not a show-stopper.
It's still possible to use quik or miboot to get a completely
"macOS free" machine, but we can leave that as an exercise for the
serious hackers.
Would that fit all the legal requirements?
It has the advantage that it's doable in the time-frame needed to
get sarge out the door.
Rick
