You may want to review Greystash’s rundown on his approach here:
https://mac-classic.com/articles/mac-os-9-on-unsupported-systems/ This thread here sorely needs review and severe clarification (and
has needed this for quite sometime). The “easy” file referenced from
DieHard, I believe refers to USB 2.0 equipped models - but I could
definitely be poorly mistaken. (Again)
I’ve mentioned before that I’ve got the 20” 1.25 GHz model, that
because of its GPU (there were two types?) that it cannot run
OS 9. Even as in the abridged chart below notes that it can?
And why no blue outline on the G4 / 800 17-inch (Flat Panel)?

So maybe here’s a little project for someone to review and update
this topic and hopefully clarify what approach works with which?
But for now, DO check Greystash’s rundown mentioned above.
Yeah, I don't like using Open Firmware either, if avoidable.

And again, if you cannot read the text in the images above,
temporarily switch your Forum theme to the old "Blu" theme.