Burn OS X Mountain Lion installer to single-layer DVD

Aug 07, '12 07:30:00AM

Contributed by: Typhoon14

If you've tried burning the Mountain Lion installer to a standard DVD, you've probably noticed that it does not quite fit. Fortunately, there is a way around this.

The problem is that the size of the InstallESD image is fixed at 4.75 GB; slightly larger then a 4.7 GB single-layer DVD. However, the actual contents of the image occupy only 4.38 GB on disk, which will fit on a standard DVD.

In order to cram Mountain Lion onto a standard DVD, we need create a slightly smaller image file of the exact same format, copy the contents over, then burn it to a DVD.

I've written a small script to make this process quick and easy. Simply paste the code below into a plain text document and save it with a file extension of ".sh" To run the script, fire up Terminal and enter "bash /path/to/script.sh". When this script finishes, you will have a new, smaller DVD image in your home folder, ready for burning.

NOTE: This script assumes you have the "Install OS X Mountain Lion" application in /Applications. It won't work if it's located elsewhere. You'll also want to make sure you have at least 9 GB of disk space free, as the script temporarily creates two additional copies of the install image.

#! /bin/bash

rm -f /private/tmp/Mountain\ Lion\ DVD\ Image\ read-write.dmg # Remove any old copies of the DVD image before we begin.

echo "Creating DVD Image..."
hdiutil create -size 4.2g -volname "Mac OS X Install ESD" /private/tmp/Mountain\ Lion\ DVD\ Image\ read-write.dmg -fs HFS+ -layout SPUD

# hdiutil attach -nobrowse /Applications/Install\ OS\ X\ Mountain\ Lion.app/Contents/SharedSupport/InstallESD.dmg
hdiutil attach -nobrowse ~/Desktop/InstallESD.dmg 
hdiutil attach -nobrowse /private/tmp/Mountain\ Lion\ DVD\ Image\ read-write.dmg

echo "Copying Mountain Lion to new image..."
cp -pRv /Volumes/Mac\ OS\ X\ Install\ ESD/* /Volumes/Mac\ OS\ X\ Install\ ESD\ 1/

hdiutil detach /Volumes/Mac\ OS\ X\ Install\ ESD\ 1
hdiutil detach /Volumes/Mac\ OS\ X\ Install\ ESD

echo "Converting to read-only..."
hdiutil convert /private/tmp/Mountain\ Lion\ DVD\ Image\ read-write.dmg -format UDZO -o ~/Desktop/Mountain\ Lion\ DVD\ Image.dmg

rm -f /private/tmp/Mountain\ Lion\ DVD\ Image\ read-write.dmg

echo "Image Creation Complete. Please burn '~/Desktop/Mountain Lion DVD Image.dmg' to a DVD using Disk Utility."
open ~/Desktop/
[kirkmc adds: I haven't tested this. Given the cost of USB sticks, and the fact that, if you do want an installer, it's better to have the most recent one, I've gone that route using Lion DiskMaker. Some people may prefer DVDs, but another factor is whether or not your Mac has an internal DVD drive; my Macs - a Mac mini and a MacBook Pro - do not, so USB is easier than using an external drive. Note: I've updated the script in the hint to the last revision below in the comments as of 8/18/12.]

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