Mac Mini G4 will not find bootable volumes

[hxctom]

My Mac Mini G4 refuses to boot from basically anything.
I have a copy of Leopard, as a bootable drive on my thumb drive.
I can boot from any computer fine, but the Mac Mini will not boot from it.

So, I used Target Disk Mode to install the OS onto the Mini G4, and it installed fine.
Disk Utility erased, formatted, ran the install, and the Macbook Pro I had the G4 hooked up to via TDM booted fine off of the Mini's HD.

I turned off both, and tried to boot up just on the Mac Mini, and it gave me the ?.
I booted using ALT to see any options to boot from, and the screen was empty.
I booted from a Tiger installation DVD to try to change my startup disk that way, and the startup disk option DID recognize Leopard on the hard drive. It confirmed to restart using Leopard on the HD, and when it restarted - still the ?

What would be the next step to troubleshoot?

 

[mikiotty]

My Mac Mini G4 refuses to boot from basically anything.
I have a copy of Leopard, as a bootable drive on my thumb drive.
I can boot from any computer fine, but the Mac Mini will not boot from it.

So, I used Target Disk Mode to install the OS onto the Mini G4, and it installed fine.
Disk Utility erased, formatted, ran the install, and the Macbook Pro I had the G4 hooked up to via TDM booted fine off of the Mini's HD.

I turned off both, and tried to boot up just on the Mac Mini, and it gave me the ?.
I booted using ALT to see any options to boot from, and the screen was empty.
I booted from a Tiger installation DVD to try to change my startup disk that way, and the startup disk option DID recognize Leopard on the hard drive. It confirmed to restart using Leopard on the HD, and when it restarted - still the ?

What would be the next step to troubleshoot?

First of all, you need several steps in Open Firmware to boot most PPC Macs off USB. It's not as easy as Intel Macs on some of them.

Any hard drive, to be bootable in a PowerPC, has to have the Apple Partition Map partition scheme. You can format the drive with the required partition scheme using Disk Utility within OS X and using the "Partition" tab. Choose the number of partitions, then click on Options and select Apple Partition Map.

Third: you can't install OS X on a PPC Mac using an Intel Mac as the installer. The OS X installer will install only the Intel binaries and the system won't boot on a PPC Mac (plus, it requires the disk to be formatted with the GUID partition scheme, which doesn't work on PPC).

You may try to burn yourself a stripped down version of Leopard that will fit on a single layer DVD, or burn the full version on a DL DVD (assuming your Mac Mini can read them).