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Roy Miller Author

Level 1

31 points

HowTo revert new MacBook Pro, Mac Pro or iMac to Snow Leopard

Hi all,

the following instructions were provided to me by our Apple Enterprise tech, and I've successfully performed these steps on a newly purchased MacBook Pro.

Please note the following - as of 15 Aug 2011:

- this technique will work on new MacBook Pro, Mac Pro or iMac computers UNTIL Apple modifies the hardware in these computers

- this technique will NEVER work on currently shipping MacBook Air or Mac Mini computers

- this configuration of Snow Leopard installed on a computer that shipped with Lion is not supported by Apple Support. It is entirely possible that after a trip for an AppleCare support incident, or the Apple Genius Bar, that the computer will return with Lion installed.

with these caveats, here are the step-by-step instructions:

---------------------------------------------------------------------

HowTo - NetRestore - Install Mac OS X 10.6.8 on new Mac delivered with Mac OS X 10.7.0

note: this only applies to Macbook Pro, Mac Pro, and iMac computers that originally shipped with Mac OS X 10.6.x.

Current Macbook Air and Mac Mini computers cannot be downgraded.

Required resources:

- another computer, running Mac OS X 10.6.8

- spare external disk

- Snow Leopard installation disc (Mac OS X 10.6.0 or 10.6.3 Box Set)

- Snow Leopard 10.6.8 Combo image file (download from Apple Support Downloads page)

- System Image Utility 10.6.8 (download Mac OS X 10.6.8 Update Combo v1.1.dmg from Apple Support Downloads page)

Procedure:

A. Create the NetImage:

1) mount the base source image (Mac OS X 10.6.3.dmg - created from Box Set Installer)

2) launch System Image Utility (from Server Admin Tools)

3) when source (from mounted image) appears in SIU screen, click Custom button

4) drag "Customize Package Selection" from Automator Library window to location

between existing "Define Image Source" and "Create Image"

5) drag "Add Packages and Post-Install Scripts" from Automator Library to location

between "Customize Package Selection" and "Create Image"

6) in the "Customize Package Selection" section:

a) expand the "Mac OS X" triangle

b) select options desired

c) collapse the "Mac OS X" triangle

7) mount the appropriate update image (Mac OS X 10.6.8 v1.1 Combo.dmg)

8) copy the MacOSXUpdCombo10.6.8.pkg package to a new local directory (Desktop/parts/)

9) drag the MacOSXUpdCombo10.6.8.pkg icon from local directory to the

"Add Packages and Post-Install Scripts" section of the SIU window

10) in the "Create Image" section:

a) select the type "NetRestore"

b) set the "Installed Volume:" field to "Macintosh HD" (no quotes, can be any name)

c) select the "Save To:" location

(will be faster to a second local internal disk)

(not faster to another partition on the same disk)

d) set the "Image Name:" field to "Snow Leopard 10.6.8 NetRestore"

e) the fields "Network Disk:", "Description:", and "Image Index:" don't

matter unless one is going to use results on a NetBoot Server

11) click the Run button

12) when the dialogs appear, ignore the text and click OK for proper completion

Dialog text: "Image creation in progress.

Cancel the image creation to proceed"

B. Post-process to create Restore Image:

1) find the directory created in the above process, named as in A.10d above

(Snow Leopard 10.6.8 NetRestore.nbi)

2) in this directory are three files:

- i386

- NBImageInfo.plist

- NetInstall.dmg

3) mount the NetInstall image (double-click the NetInstall.dmg file)

4) navigate into the Contents of the package, to: System/Installation/Packages/

5) copy the System.dmg file out to desktop or other work location

6) rename System.dmg to meaningful name, such as "Snow Leopard 10.6.8 System.dmg"

7) copy this .dmg file to external, bootable, Snow Leopard 10.6.8 system disk (install in /Users/Shared/)

C. Install Snow Leopard 10.6.8 on new MacBook Pro or Mac Pro

via command line:

1) boot MacBook Pro or Mac Pro from external source prepared in B.7

2) open Terminal

3) find the restore target device specification

a) run the command "diskutil list"

b) look for a 650 MB partition, labelled "Recovery HD" (likely disk0s3)

c) the target partition should be immediately prior to the "Recovery HD" partition

d) for a new computer with a 500 GB drive, this partition should be

labelled "Macintosh HD", with a size of 499.2 GB

e) make note of it's Device Identifier, likely disk0s2

4) issue the following asr (Apple Software Restore) command

sudo asr restore --source "/path/to/restore.dmg" --target /dev/disk0s2 --erase

(replace "/path/to/restore.dmg" with the path to the location and name used in step b.7)

5) this process proceeds and completes quickly, about 3-5 minutes. This is due to

the "--erase" parameter; it indicates a block-copy operation

If the process seems slow, likely the "--erase" option was omitted and

the copy is being done as a file-copy operation. Quit (ctl-c) and

examine the command used...

via DiskUtility GUI:

1) boot MacBook Pro or Mac Pro from external source prepared in B.7

2) launch /Applications/Utilities/DiskUtility.app

3) select the computer hard drive (typically "Macintosh HD")

4) click on the "Restore" tab

5) click on the "Image..." button to specify the "Source"

6) navigate to /Users/Shared/ and select the "Snow Leopard 10.6.8 System.dmg" file

7) drag the computer hard drive volume (Macintosh HD) to the "Destination" field

(note: grab the volume, not the disk!!)

8) enable the "Erase destination" checkbox

9) click the "Restore" button

10) in the ensuing "Are you sure?" dialog, click the "Erase" button

11) authenticate with the local admin credentials

Apple Tech recommends leaving the Restore partition alone, and installing in the "Macintosh HD" partition only

commands to know:

- asr

- diskutil (diskutil -list to see partitions)

- hdiutil

Posted on Aug 15, 2011 9:00 AM

364 replies

jimtet

Level 1

4 points

Oct 31, 2011 1:48 PM in response to Tech Harmony

I have been following everything I could read about going from lion to 10.6.8. New iMac purchased this month (Oct) and the build no is 11C74 which is not listed and neither is the SN which starts with D25G51. Before I start this process again I want to know if it will work. I was told by tec support after two hours on the phone that it would not work on a new iMac shipped with lion. I asked Roy to clairfy this for me but he has not replied yet. I ask Roy if I could install 10.6.8 on a external disk and run it on this lion based iMac and still no reply. I love my apple computers and usually can figure things out myself, but this has me stumped so far. I have a 2006 iMac with 10.6.8 and it works fine with my old apps. I need some help on this.

Thanks for any help you can give me

Jim Tetterton

Oct 31, 2011 2:52 PM in response to Roy Miller

Thank you Roy! Your steps worked as you'd written them.

I did go about things a little different. My early 2011 MacBook Pro and my late 2008 MacBook both have Lion installed so I didn't have a 10.6.8 system. But, I do have a 10.6 Snow Leopard Server VM.

After updating the VM to 10.6.8 I followed steps A1-12 and steps B1-6 using the SLS VM. Something was off with my VM as it KP'ed once, but running through the process again it finished successfully.

I took the resulting system.dmg file and restored it to a USB thumb drive. Booting from it failed, but it showed me that the image was good. I then partitioned my MBP's hard drive and restored the system.dmg file to the new partition. Everything booted as normal.

I did read in this thread that someone had a performance issue. I ran geekbench with Lion an got about 9,883. After Snow Leopard booted I ran geenbench from the Lion parttion and it reported back with about 10,083.

Thanks again for your write up. It really saved me. Now I can go play Diablo 2.

- Reuben

Roy Miller Author

Level 1

31 points

Nov 1, 2011 6:27 AM in response to jimtet

Hi JimTet,

Tech Harmony provided an answer for you:

@jimtet, Doesn't sound like the Apple Techs you reached were able to run through "The Procedure".... it does work for iMac folks but the verdict for iMac'cers is that you'll get more performance if you request and utilize the factory install discs from Apple. If you call Apple back, they should send you the discs for 0-15$, depending on who you get. These special factory install discs for your iMac are probably all-white and have a version of 10.6.6 or 10.6.7 that was especially made for your iMac.... then you will be able to update from there as you please.

This suggested method would likely be the easiest method to install Snow Leopard on a new iMac. The key to whether installing Snow Leopard on a computer released with Lion installed is the degree to which hardware changes have made in the Lion-release iMac, or if the hardware is the same that was released with Snow Leopard.

A couple of thoughts have occured to me, regarding your situation. First, the disclaimer: I've never worked with an iMac, so have no first-hand experience with them. My recent Mac exposure has been limited ( 😉 ) to: Mac Pro, MacBook Pro, MacBook Air, MacBook, Mac Mini, and Xserve.

anyway, that aside, I have two suggestions:

- try connecting your two iMacs via firewire, and booting the new one from the 2006 iMac with Snow Leopard installed. I've never tried exactly this myself, so there may be some reason why it wouldn't work.

This process would be:

1) power up the new 2011 iMac

2) with the old 2006 iMac off, connect a firewire cable between the two iMacs

3) power on the old 2006 iMac, holding down the "t" key

4) when the firewire icon starts gliding across the old 2006 iMac screen, release the "t" key

5) when the old 2006 iMac disk appears on the desktop or mounted Volumes area of a Finder window on the new 2011 iMac, open System Preferences.

6) in the "Startup Disk" System Preference Pane, select the old 2006 iMac disk to boot from

7) enter passwords in the ensuing dialogs if necessary, and click the restart button when offered

if the system boots, and runs, and your apps function, you will know that the new 2011 iMac runs fine from Snow Leopard. You can use Carbon Copy Cloner or SuperDuper! to clone the old 2006 iMac system to a clean external disk, and use that disk to boot and run your new 2011 iMac.

Note: to make the Target-mode boot process above easier, it might be worth renaming your disk on the old 2006 iMac to something unique, if not already done. It can be hard to figure out which "Macintosh HD" volume is which, when there are more than one!

The other idea is to run "The Procedure", with an install target (Part C) of an empty external disk. Once completed, this could be used to boot your new 2011 iMac in Snow Leopard, while maintaining the Lion installation on the new 2011 iMac internal disk.

so, options abound - unfortunately there is no remedy that is not a bit of an adventure. Only you can decide whether it is a worthwhile endeavor for you to attempt to revert a Lion computer to Snow Leopard.

cheers!

rpg2288

Level 1

4 points

Nov 1, 2011 8:56 AM in response to Roy Miller

....btw, installed the firmware update (2.3) on the newest MBP (15") (from 10/24/11). Everything seems o.k.

Nov 5, 2011 4:35 PM in response to Roy Miller

I have both Lion and Snow Leopard running on a Mid 2011 Lion machine with a lot less hassle than you guys are going through. See this post for the details.

https://discussions.apple.com/thread/3466013?answerId=16639737022#16639737022

It runs smoothly as well for me.

Nov 9, 2011 9:23 AM in response to Roy Miller

Is there a list of disc part numbers that came with 10.6.6 or 10.6.7 for the various Early 2011 MacBook Pros?

I gather that installing from these is probably the easiest option.

DewChugr

Level 1

0 points

Nov 11, 2011 8:39 PM in response to Roy Miller

I found this thread because I don't want to purchase new versions of Adobe CS and Office right now, as well as some other software. Here's my story of installing 10.6.8 on a second partition on a BRAND NEW Macbook Pro....

I have a new 13" Macbook Pro, got it this past Wednesday, the 9th, it's the newests model. Macbook Pro 8,1 2.4GHz 8GB ram 500MB HD. It came loaded with 10.7.2 which I updated with the software updates when I got it. I have not done the v2.3 EFI firmware update at this point.

I have two partitions, one with the 10.7.2 and one with 10.6.8, this is how I did it.

I created a second partition, 50 GB. I have a 4 year old white Macbook I got in June of 2007, not sure the model, but it's core 2 120 GB HD and 4 GB ram. I used an external USB drive for this. The old Macbook came with 10.5, but I have the DVD from when I updated it to 10.6.3. I was going to use a flash drive, but I only had a 4 GB available.

After I created the second partition I hooked the USB HD to the old Macbook, inserted the 10.6.3 DVD and installed it onto the external drive. After the install I installed all software updates, including 10.6.8. The machince booted and ran as expected. After that I hooked the drive up tp the new Macbook Pro. I used Carbon Copy Cloner and copied the 10.6.8 to the new partition on the new Macbook Pro. When that finished I opened system preferences and selected the new 10.6.8 partition as the start-up disk and restarted the computer. The computer booted as expected (hoped). Someone mentioned a 10.6.8 combo updater on the Apple site. I downloaded MacOSXUpdCombo10.6.8.dmg and installed it, just for the heck of it. I ran geekbench 2.1.13 on both the 10.7.2 and 10.6.8 boots and the 10.6.8 showed over 100 higher.

I haven't used 10.6.8 much as I've been playing with Lion for now, but everything seems to be working. Gestures, dual screens, wireless, etc. So, yes, it appears that you can get it to work and in my case with very little trickery.

Hope this helps someone.

rsx-s

Level 1

0 points

Nov 18, 2011 12:21 PM in response to Roy Miller

I just purchased a late 2011 MBP 2.4 i5 four days ago thinking I could easily dual boot 10.6 and lion. Boy was I wrong.

Is it time to return this and look for an early 2011 MBP, just so I can run 10.6 on a separate partition???.

Has anyone had success downgrading to 10.6 or creating a dual boot environment of lion and snow leopard, using a retail copy of 10.6??

At the very least can I install Snow leopard on an external usb hard drive??? Or will that not even install properly???

p.s. I don't have another legacy mac to install snow leopard onto, so I cant attempt the Carbon Copy Cloner method mentioned.

Nov 18, 2011 12:43 PM in response to rsx-s

Very new macs may not support a default install of SL. I would like to ask you ‘why did you buy it if you wish SL and only SL?’. but am not going to ask you that. I cannot bet I am right, but I may write about my installing Tiger on my first MBA some 3 years ago. That machine came with 10.5.1, therefore Tiger could not be installed. I did the following trick, from curiosity (also wished to test my Apple intelligence):

- Installed an intel Tiger unto an external drive using a MacBook, which natively supported Tiger

- when ready, connected external drive to MBA, restarted and booted from the external drive

- it worked!

- Rebooted from genuine MBA install DVD, made two partitions of the disk

- cloned the Tiger external disk unto one partition of the internal MBA disk

- Booted into Tiger running natively on that Air

All was OK. My curiosity was satisfied, all worked, my native intelligence was also well appreciated.

I cannot bet this trick may work for you, but you may try. Depending on your ability to repeat the same steps with newer OSs, but in similar circumastances, it may take several hours. If this works, go ahead.

Just for my curiosity: why would you like to revert to SL on a very new mac machine?

Roy Miller Author

Level 1

31 points

Nov 18, 2011 12:57 PM in response to rsx-s

@rsx-s - the bottom line of whether you can boot a current Mac from a Snow Leopard disk and have full support of all the hardware in the new Mac depends upon whether new hardware components have been integrated into the current version of the Mac in question since Lion was released.

If no hardware changes were made, then the current Mac can run under at least Mac OS X 10.6.8, and perhaps slightly older versions, if the hardware configuration ever shipped with the earlier version of the OS.

Once hardware changes have been integrated into the computer, the older systems won't support that new hardware - the drivers were never compiled into the older OSes, because of course, such a configuration didn't exist when the older version of the system was compiled!

One thing is for sure - none of the "retail" versions of Snow Leopard (v10.6.0 & v10.6.3) will boot any of the currently offered hardware. Therefore "The Procedure" and its derivatives and alternate methods, as discussed in this thread.

It makes no difference whether the Snow Leopard OS is installed on the internal hard drive, a partition on the internal hard drive, or an external hard drive.

Regardless of any of our (the Users) desires, we will all eventually be running Lion or a later OS version on our newly purchased Macs, or have switched to non-Mac alternatives.

One of the easiest methods I've heard of, included in this discussion thread, is to call Apple Care and ask for a grey boot disk for the MacBook Pro as it was delivered immediately prior to the release of Lion. This is likely Snow Leopard version 10.6.6 or 10.6.7. It may cost $15-$20 to get - but if it will boot your new MBP, then you can install from that and upgrade to SL 10.6.8 via Software Update.

cheers!

Roy Miller Author

Level 1

31 points

Nov 18, 2011 1:05 PM in response to Cattus Thraex

Hi Cattus Thraex,

I cannot bet this trick may work for you, but you may try. Depending on your ability to repeat the same steps with newer OSs, but in similar circumastances, it may take several hours. If this works, go ahead.

this "trick" may work for newer hardware, especially if one is not using the "new hardware" for which the old OS has no drivers. For example, if the new hardware were only the addition of Bluetooth, and the user never uses or configures Bluetooth, than that user would likely never know the difference.

However, if the "new hardware" included a new graphics card, which didn't exist at the time the old OS was compiled, this "trick" would likely not work flawlessly.

Just for my curiosity: why would you like to revert to SL on a very new mac machine?

many reasons exist, including software programs that don't run (yet) on Lion, business and organizational enterprise networks that don't allow Lion (yet) due to incompatiblities with network and security schemes, and the time-honored favorite of "the old system works well, and I know how it looks and how to configure and use it".

This is a subject that some are very passionate about, and one that is often very subjective.

cheers!

Nov 18, 2011 1:16 PM in response to Roy Miller

I agree: yes, there are apps, which cannot run in Lion any more (Rosetta needed); or apps, which have not been updated. Nevertheless, Apple will not develop any majhor improvement for older systems, SL included, so the option seems to be 1. install Lion immediately v. 2. postpone installing Lion.

Those wishing very new machines should know that oldr systems are not supported by default, and installing SL may be or (rather) may not be possible any more.

rsx-s

Level 1

0 points

Nov 18, 2011 1:16 PM in response to Cattus Thraex

I need snow leopard to run Adobe CS5 on a daily basis( I freelance after school), and am learning film editing with Final Cut Pro 7.

With a dual boot, I can still use my legacy apps in Snow Leopard over the next few months while I wait for Adobe CS6 to be released for Lion. Having Lion on another partition allows me to slowly install new software as it is released.

My 3 year old iMac mobo died recently and the screen was starting to go, so I bought the 2.4 MBP 13" since the early 2011 MBP were out of stock at my local Apple Store. I know the 13" is mighty powerful enough to run Photoshop, Dreamweaver and Final Cut. The 15" is out of my budget and is to big to lug around campus.

Snow Leopard is only a couple years old, and I am a student/part-time designer, thus cannot afford to purchase new licenses for software thats still usable and relevant, let alone less than 24 months old.

Nov 18, 2011 1:17 PM in response to rsx-s

This is a sound argument too.

DewChugr

Level 1

0 points

Nov 18, 2011 1:19 PM in response to rsx-s

CS5 should run on Lion, I have used CS4 on it.

HowTo revert new MacBook Pro, Mac Pro or iMac to Snow Leopard