Create a Leopard to Snow Leopard Upgrade NetInstall Image

UPDATE (10/15/09): I’ve gotten mixed results from some individuals who’ve tried the workaround with 10.6.1. I’m working on and testing an extended workaround that should fix the problem for everyone. Look for that info soon.

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UPDATE (10/13/09): I’ve updated the article (and posted it as new) with a workaround for the issue that prevented additional packages from being installed. I submitted the bug that this workaround avoids to Apple — id #7247968 — on September 23, 2009.

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This post is a Snow Leopard update to a process I wrote about when Leopard (10.5) came out. This post will tell you how to create a NetInstall image that will upgrade a Mac running Leopard to the latest version of Snow Leopard in one step. It will also work to upgrade a Mac running Tiger to the latest version of Snow Leopard.

What You’ll Need

  1. A 10.6 software license, or individual retail copy of Leopard, for each computer you are upgrading from Leopard or Tiger to Snow Leopard — this is easily overlooked, so let’s keep things legal.
  2. A read/write disk image (.dmg) of a Mac OS X v10.6 Snow Leopard Install DVD (i.e. not shipped with a computer). You’ll convert this to read-only after making a small modification to one of the files.
  3. One build computer running Snow Leopard with the latest version of Snow Leopard’s Server Admin Tools installed (10.6.0 as of this writing).
  4. A computer running OS X Server providing NetBoot services — Tiger, Leopard, and Snow Leopard Server will all work
  5. A copy of the OSUpgrade.pkg found on the Install DVD at /Volumes/Mac OS X Install DVD/System/Installation/Packages. This is a hidden folder, so use Go to Folder from the Finder’s Go menu to reveal it.
  6. Optional: the latest Combo Updater — 10.6.1 as of this writing. (Yes, it’s not a Combo Update, but only because it’s a .1 updater.) Continue reading