Okay, so seeing that it took me a good deal of time to get this working on my eMac 1.25 piecing together various instructions on here and ThinkClassic, here's a step by step to get a working install of OS 9 on the eMac that I did.
1. Download and burn the Mac OS 9.2.2 for Unsupported G4s from here:
http://macos9lives.com/smforum/index.php/topic,2143.0.html2. Insert the burned CD into your eMac and boot holding down Cmd+Opt+O+F. This enters Open Firmware.
3. In Open Firmware enter the following - (this spoofs your eMac's CPU into one recognized by OS 9) - Hit return at the end of each line.
" /cpus/PowerPC,G4@0" find-package if drop " /cpus/PowerPC,G4@0" find-device 80010201 encode-int " cpu-version" property then
device-end \ PLX-OS9-PATCH
boot cd:,\\:tbxi
4. Your eMac should now proceed to boot up from the Mac OS 9 CD.
5. Before doing anything. Partition your drive using Drive Setup.
6. Click on Initialize and then 'Options'
7. Create a 1GB Partition for OS 9, a 8GB Partition for Tiger and the remaining for Leopard. Or if you just want one version of OS X, then 1GB for OS 9 and the remainder for Leopard/Tiger.
8. Now run the Apple Software Restore and target the 1GB Partition, this carries out your OS 9 install.
9. Now go ahead and install Tiger and/or Leopard on the remaining partitions. Make sure not to erase/change your partitions from the OS X installer.
10. Once you have OS X set up, download tbxi-enabler and the ATI,Merlin patches that MacTron uploaded at the top of this Thread on your eMac.
11. Copy all the ATI/OpenGL extensions to the Extensions Folder, overwriting the older versions.
12. Copy tbxi-enabler to the System Folder. *do not rename it*.
13. Remove Mac OS ROM.
14. You should now be able to boot up with OS 9 holding Option during boot.
P.S. The logic I do with the partitions is that I create the smallest partitions for the Older OS's and then have the newest OS on the largest partition. All the applications are then located on the largest partition. 1GB for OS 9 should leave about 575MB free for Control Panels, Extensions and so forth you want to install, which should be plenty, but feel free to make a larger OS 9 partition if you wish.
Please let me know how you get on.