Doing this will also allow owners of the current 21 and 27 inch iMacs to downgrade to Snow Leopard. I have a 27" iMac running Snow Leopard, the OS it shipped with. Apple started to only sell it with Lion once it was released.

Instead of playing with terminal, defaults, and killall, you can simply open a Finder window of the 10.6/10.63 Installer disk, then press Cmd-G: in the popup type

System/Installation/Packages

(no trailing "/") and press return, it will show the content of that hidden folder.
You will have to do this again, in another window, for the 10.6.7 Installer disk.

I think he means "shift" command-g, which is the "go to folder" command.

cmd shift G

Like the original poster, I've found a number of machines that require a Snow Leopard installer higher than what may be available (since the owners of those machines have invariably lost their discs and/or have bricked their optical drives). My method (and I will freely admit this was not my original idea) is to use a disk image of a 10.6.8 working HD that has not yet been through the personalization. I "restored" this image to a few destinations—a toolkit, of sorts—a USB hard drive, FireWire HD, USB flash drive, and even a SDHC card. Then I went through the personalization with each one. Finally, I copied the original disk image (as a .dmg) to these destinations. Obviously, you need something like a 16GB flash drive or SDHC card.

I can then boot the intended "target" machine using one of these devices and use Disk Utility to restore the "virgin" 10.6.8 disk image to the machine's hard drive. With a FireWire machine, however, it's often easier to boot the target machine in target disk mode, plug it into my iMac, and do the restore from there.

As a side benefit, there are very few software updates then required.

Restoring is different to Installing.
I build "Vanilla 10.6.8" unbooted images with a few extra packages tagged on using InstaDMG which get laid down on compatible hardware using Deploystudio or SIU (System image utility is sort of redundant for me now)

However if you have to do system upgrades this is a handy hint with the hardware which will not boot from 10.6 or 10.6.3 retail.

#!/bin/bash
clear

destination=~/Desktop/Mac\ OS\ X\ Install\ DVD

#make destination folder
[ ! -d "$destination" ] && mkdir "$destination"

#make sure disc is in drive
while [ ! -d /Volumes/Mac\ OS\ X\ Install\ DVD ] ; do
echo Please insert Mac OS X Install DVD and press Enter
read
done

#get device node for block copy
device=$(diskutil info /Volumes/Mac\ OS\ X\ Install\ DVD/ | grep Node | cut -f2 -d:)

#create disk image from device (retains Finder window custom background)
echo "Creating Disc image at $destination, please wait..."
/usr/bin/hdiutil create -srcdevice $device -format UDRW "$destination"/Mac\ OS\ X\ Install\ DVD.dmg

#disk image using source folder (loses custom Finder background)
#/usr/bin/hdiutil create -srcfolder /Volumes/Mac\ OS\ X\ Install\ DVD/ -format UDRW "$destination"/Mac\ OS\ X\ Install\ DVD.dmg

#eject media
/usr/bin/drutil eject

#tell user to take out disc
echo -e $'\a'$'\a'$'\a'$'\n'"Please Remove the disc and press Enter"$'\n'
read

echo "Modifying Image"

#mount r/w image
hdiutil attach "$destination"/Mac\ OS\ X\ Install\ DVD.dmg

#expand OSINstall.mpkg
/usr/sbin/pkgutil --expand /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.mpkg /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.expanded

#modify Distribution script in place with no backup
/usr/bin/sed -i '' "s/modelProp\ \=\=\ hwbeSupportedMachines\[i\]/1/g" /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.expanded/Distribution

#modify Distribution script in place with backup (for sissies)
#/usr/bin/sed -i '.original' "s/modelProp\ \=\=\ hwbeSupportedMachines\[i\]/1/g" /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.expanded/Distribution

#remove original OSInstall.mpkg package
/bin/rm -rf /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.mpkg

#flatten new package
/usr/sbin/pkgutil --flatten /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.expanded /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.mpkg

#remove expanded folder 
/bin/rm -rf /Volumes/Mac\ OS\ X\ Install\ DVD/System/Installation/Packages/OSInstall.expanded

### image is now ready to be burned ###

#eject disk image
hdiutil eject /Volumes/Mac\ OS\ X\ Install\ DVD/

#burn disc image
/usr/bin/drutil burn "$destination"/Mac\ OS\ X\ Install\ DVD.dmg

echo -e $'\a'$'\a'$'\a'$'\n'"Disc Complete, Please Remove the disc"$'\n'

Thanks for this. I am trying your .command file but it's not executing properly. I am starting with a mounted .DMG of 10.6.7 on my desktop and it's appearing as "Mac OS X Install DVD."

This is the error I get, when I try your .command file, in Terminal:

"exit;
destination=~/Desktop/Mac\: bad interpreter: No such file or directory
logout"

Any help?

I also don't see any mention of the print drivers in your script. They're handled?

Thanks again.

all was going good and i thought i cracked it, until i tried to restore the modified image with SuperDuper. i also tried with disk utility and that didnt work neither. it return an error
"Retore Failed"
Could not find any scan information. The source image needs to be imagescanned before it can be restored.
so i tried to scan the image for restore and that failed also.
super duper log reports a segment fail
| 01:04:39 AM | Error | sh: line 1: 9052 Segmentation fault asr -source '/Users/Rivers/Installers/Mac Installers/Mac OSX/Mac OS X Install DVD.dmg' -target '/Volumes/Mac OS X Install DVD' -erase -noprompt -noverify

just for clarification i was trying to restore to an external usb HD. i tried multiples aswell to rule out that.
any ideas?

All went well un until the point where i came to restore the image on to a partition. both superduper and disk utility didnt work.
superduper return this in the log.
| 01:04:39 AM | Error | sh: line 1: 9052 Segmentation fault asr -source '/Users/Rivers/Installers/Mac Installers/Mac OSX/Mac OS X Install DVD.dmg' -target '/Volumes/Mac OS X Install DVD' -erase -noprompt -noverify
disk utility said that the image needed to be scanned for restore, which i did, but this didnt work as it returned a null error.

any ideas? need help fixing this bad.

If you're going the 'restore' route to image a machine to a known state, and don't want to wait to download and install all of the updates to keep your 10.6 machine up-to-date, then InstaDMG is for you. It's free. You give it your retail 10.6 disk, and it does all the work to create a minty-fresh up-to-date disk image that you apply to a compatible Mac.

I was having an error when copy-paste text in Text Wrangler to make the command, like other users. I used this command file (same text) and worked ok: http://www.brunerd.com/blog/wp-content/uploads/makeUniversalSnowLeoDisc.command.zip

All went well, from macbook pro 10.6.7 installation disk to universal 10.6.7, but when installed on late 2011 iMac, the wifi is not working and the spanish usb keyboard has some keys wrong. Seems like the drivers for the wifi card and the keyboard are different.

Any solution to install the correct drivers?

Thanks.

Has anyone tried this on a late 2007, early 2008 macbook such as macbook 3,1? that is what i have. it originally came with 10.5 but I was curious to upgrade it with a 10.6.3 upgrade disc i have for my other mac.

WoodHeBe, you are my hero!!!!!
for weeks i've been struggling to find a solution for my crashing MacBook Pro mid 2010, and my last resort was to roll back to the original OS - snow leopard, however because i did not have the install CD, no image i downloaded off the web worked for me - i almost gave up.

well, thanks again.

CREATE A BOOTABLE UNIVERSAL INSTALL "DVD"...
Thank You to OP (and others) for this overview!
I modified instructions to create a Bootable Universal Install DVD.
This allows me to make a Bootable Master Universal 10.6.7 Install DVD, which I can also restore to a USB drive...

Modified Steps to Create a Bootable Master Universal 10.6.7 Install "DVD"
* Launch 'Disk Utility'
* Drag Non Universal 10.6.7 Install DVD.dmg to left window pane of Disk Utility
* Highlight/Choose 'Mac OS X Install DVD 10.6.7.dmg" in Disk Utility side pane.
* Choose "Convert" function in Disk Utility Toolbar (Or Images > Convert in Menu Bar)
* Convert dmg to DVD/CD Master as Image Format ( Encryption = none)

This creates a Mac OS X Install DVD 10.6.7.cdr (".cdr" extension)
Mount the: Mac OS X Install DVD 10.6.7.cdr
You are now going to work on the Mounted Image of this .cdr DVD/CD Master ...

I used Onyx to reveal the invisible files in finder
Onyx > Parameters > Finder > "Show hidden files and folders". (This restarts the Finder, reveals invisible files).

Now replace the OSInstall.mpkg and printer related packages as per the original instructions above, within the MOUNTED IMAGE of the Mac OS X Install DVD 10.6.7.cdr .

After successfully replacing the files as per the original instructions above, unmount the image, and the Mac OS X Install DVD 10.6.7.cdr is now a fully modified DVD/CD Master.
(Used Onyx again, unchecking the "Show hidden files and folders" option. This again restarts the Finder).

Now, "lock" the newly modified Mac OS X Install DVD 10.6.7.cdr. DVD/CD Master.
Still using Disk Utility, again highlight the Mac OS X Install DVD 10.6.7.cdr. in the side window pane.

Choose "Burn" from within Disk Utility and Burn to a blank DL DVD.
Voilá : I now have a Bootable Master Universal 10.6.7 Install "DVD" (I hope)...