10.4: Create a single Universal binary bootable disk

Mar 22, '06 05:42:00AM

Contributed by: rolfk

Tiger only hintWithout a Universal binary, Mac OS X 10.4 System Administrators like myself must effectively double their responsibilities and maintain two operating systems, one for each platform. Ideal would be an OS X system which is Universal, and therefore able to boot both Intel and PowerPC Macs. Apple is probably releasing a Universal binary Mac OS X 10.5, but can we wait? No!

My goal was to try to create a Universal binary Mac OS X System in an easy way, so other System Administrators or interested people can also recreate it. I started by reformatting an external FireWire drive on an iMac G5, and created four partitions on it:

  1. 10 GB "MacOSX PPC"
  2. 10 GB "MacOSX INTEL"
  3. 10 GB "MacOSX UNIVERSAL"
  4. 70 GB "Spare"
I then copied a G5 iMac's OS X 10.4.5 System onto the MacOSX PPC partition, and an Intel Mac's OS X 10.4.5 System onto its appropriate MacOSX INTEL partition. This can be done such that you can actually boot from both partitions, as shown by Jonathan Rentzsch and by this hint posted here previously. Now we only need a way to combine the two systems into one. Is it possible? Yes it is!

After I read this very interesting article from Andrew Mortenson, wherein he describes how he succeeded in creating a bootable Universal binary Mac OS X System with Radmind, I figured that there could maybe be an easier way to accomplish this.

Based on the assumption that all the important system parts are already Universal binary, and that the Intel 10.4.5 System is only missing some hardware-specific files for the PowerPC platform, one could maybe clone OS X Intel on top of OS X PowerPC. That way, all the PowerPC-only kext files, etc., would be replaced with Universal binary files. Other system files, specific to the PowerPC platform, would be left alone..

I tried it and it worked! The procedure was very easy, since I had already prepared an external FireWire disk with four partitions as described above. From there, I just did this:

  1. I booted an Intel iMac, and connect my external FireWire disk. I then cloned the MacOSX PPC partition to the MacOSX UNIVERSAL partition on the FireWire Disk, using CarbonCopyCloner (in file copy mode).
  2. After that, I cloned the MacOSX INTEL partition on top of the files from the PowerPC partition on the MacOSX UNIVERSAL partition, also in file copy mode.
  3. I then selected the MacOSX UNIVERSAL partition as the startup volume in the Startup Disk pane in System Preferences, and restarted. The MacOSX UNIVERSAL partition booted the Intel iMac without any problems.
  4. I then connected the external FireWire Disk to a PowerPC iMac, started it up, and pressed the Option key immediately. After a few seconds, I got a screen where I could choose which system to boot from. I again chose MacOSX UNIVERSAL as the startup volume, and found that the PowerPC iMac booted just fine.
That's it; a single universally bootable OS X system...

Caution: I do not recommend using this image for production or mass deployment. This hint is only intended for Administrators, since update mechanisms may fail, and Apple could change something at any time such that this Universal binary image may not work anymore!

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