Articles from The Mac Elite, CubeOwner & more

Saturday, December 22, 2007

Steps for booting from drives other than the primary CD/DVD

The following is a small variation of the method from the first article:
Instead of assuming that the Mac OS X Install DVD can be booted from the built-in optical drive connected in the standard location the following code (downloadable as 867MHz.txt) brings up the systems boot menu to start the installation from any accessible boot device, including for example external DVD drives, FireWire hard drives and even NetInstall servers.

\ Claim first CPU runs at 867 MHz, and let the user select the Install DVD:
dev /cpus/@0 d# 867000000 encode-int " clock-frequency" property

boot cd:,\\:tbxi has been replaced by multi-boot; the other changes are purely cosmetic.

Steps to perform (as previously described):

  1. Move the file 867MHz.txt to the root of the primary partition on your master drive (originally Macintosh HD, where the System folder usually resides).
  2. Reboot
  3. Press and hold Command-Option-O-F until you enter the Open Firmware monitor.
  4. At the Open Firmware command prompt ("0>") enter boot hd:\867MHz.txt.
  5. Now it is your responsibility to select the Mac OS X Install DVD, wherever you placed it.

I still recommend the first method in most cases, but the steps here can be helpful when your Mac doesn't have an internal DVD drive.

I'm convinced that any changes to the nvrams content should be avoided for the application of this technique because they carry the risk of complications, might not be removable as clean as it seems on the first sight and the installer on the DVD only has to be fooled once — keep a simple trick easy !
(This modification will never survive the next reboot.)

PS: I don't think an adjustment is necessary for dual CPU systems as any Apple-supplied configuration has both CPUs running at the same clock so I expect the installer to only check the first one. Has anybody tried this ?
(Otherwise see the first article.)

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