Installing CentOS on PowerMac G4

I am trying to install CentOS on an old PowerMac G4 (because I want to set up a FreeIPA server).

I created a bootable USB drive with an iso image of CentOS with the following command in Linux: dd if=CentOS-6.8-i386-LiveCD.iso of=/dev/sdb

I plugged the drive into the Mac. As I heard the startup chimes, I pressed the option key and it got me to the boot options menu. There, however, I only see the hard drive, no USB drive.

Why can I not choose to boot for the USB drive?

Simple.

PowerPC G4 computers cannot boot via USB. They are simply too slow. That option only became available with the introduction of faster Intel machines. Think of this. Where were bootable thumb drives during the last century PowerMac G4 era? Simply not invented. You may have more success if you use a FW800 bootable external drive whatever that operating system may be on it.

OK. I see. I might just build a new pc from scratch and use it as server. No need fussing around with my old G4. Thanks for the reply.