I just got an old iMac G3 Slot Loading and am trying to install OS X 10.4. I just swapped the HDD and RAM for something bigger, so there's absolutely no operating system on this system right now.
The issue I'm having is I'm receiving an alert:
You must update your computer's firmware before installing Mac OS X.
I found the files on the Apple site, however, I have no idea how I can install the files if I have no operating system to boot from. Any help will be great.