linux no longer bootable after mac os upgrade

[Ric Otte <ric@otte.ucsc.edu>]

I recently managed to get linux installed on my titanium powerbook,
(it took me several days, because I had problems with some kernel
options and X).  It is a dual boot machine, and things were working
fine until my kid updated the mac osx software (by clicking the
automatic software update function).  The problem is that now I no
longer get the choice of linux or mac at boot time; the machine
automatically boots into the mac operating system.  I believe the
Linux operating system is still there (the mac partition is still
small), but I don't know how to get access to it.  I assume if i ran
ybin again, it would set things right.

So, is there any way to reset the way this machine boots, or do I have
to reinstall from scratch and put my kid up for adoption?

Thanks,

Ric