iMac G4 not booting from install USB

[kadinthegamer]

Hello,
I just got an old iMac G4 1GHz 15" model from a neighbor.
The iMac ran Mac OS X 10.4 Tiger, and I wanted to upgrade it to 10.5 Leopard.
However, since the optical drive was dead, and the iMac would not accept a newer Apple external super drive, I tried something else.
Using a MacBook running Mojave, I erased and reformatted a 16 gig USB drive to the Mac OS Extended Journaled format.
Afterwards I created a bootable USB drive by restoring the drive to the Leopard install disc.
All worked fine and the USB drive showed up as a DVD installation disc when I plugged it into the iMac, until I tried to use it.
I launched the installation and the iMac restarted. The instruction PDF that came with the installation said that the iMac should boot right to the installer. That didn't happen. It booted to the hard drive.
Then I found something a little strange: when checking disk utility, only the hard drive showed up, while both the hard drive and the USB drive (recognized as a DVD) were visible on the desktop.
Is this a problem with the iMac being able to boot from a DVD but not a USB drive? How do I get this upgrade to proceed?
Additionally, the only keyboard I have is a wireless windows keyboard, and all the key combos I've tried on startup have not worked.
Any help would be greatly appreciated! I hope you can view the picture I attached of the disk utility and desktop.
Thank you!

 

[chscag]

Is this a problem with the iMac being able to boot from a DVD but not a USB drive

That's correct. It will boot from the hard drive or Firewire but not USB. However, there are work arounds. This has been brought up before in these forums. Sorry, I don't have a reference to give you but you should be able to find it from a forum search.

Hopefully someone with a better memory than me will chime in.

 

[kadinthegamer]

It will boot from the hard drive or Firewire but not USB.

Firewire sounds promising. If I got an external drive with a firewire 800 to 400 converter, do you think that would work?

 

[Juicy Box]

Firewire sounds promising. If I got an external drive with a firewire 800 to 400 converter, do you think that would work?

I have booted my old Macs with external FW drives.

Actually, I even used an old iPod with FW dock cable and booted MacOS from it.

You could probably find a cheap FW enclosure on eBay, just put in your own drive.

 

[kadinthegamer]

You could probably find a cheap FW enclosure on eBay, just put in your own drive.

Alright, I'll buy an enclosure and see what happens! Thanks!

 

[Juicy Box]

If you have access to another old PPC Mac, Target Disk Mode might work as well.