I tried booting Debian 9.2.0 live netinstall and live.
Both started up and gave a black screen with white writing and then a screen similar to:
Select CD-ROM Boot Type :_
Nothing I did on the attached USB keyboard had any affect, nor did anything I did with the mouse.
I received the machine from someone that upgraded to a newer machine. The hard drive was mostly wiped clean and Apple no longer supports the over-the-network install.
My hope was to replace an iMac G5 (running Xubuntu) with this machine since the G5 is so incredibly slow (radeon driver issues most likely).
Any suggestions on how to get the machine running x86_64 would be welcome - I'm hoping to be able to build Android and Android apps on the machine so it needs to be 64-bit.