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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:

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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

Top-ranking reply

zirkenz

Level 1

0 points

Posted on Sep 9, 2011 6:28 PM

okay i got to step:

b7) copy this .dmg file to external, bootable, Snow Leopard 10.6.8 system disk (install in /Users/Shared/).

Don't understand what this means. Right now i copied to my imac desktop and renamed the system.dmg file (from the netinstall mount, system/installation/packages) as you said to Snow Leopard 10.6.8 System.dmg. This file is ow sitting on my imac desktop. What do i do next? I dont understand part b7. Where is the external bootable snow leopard system disk and where is install in /Users/Shared/ ?

by the way the renamed system.dmg file to Snow Leopard 10.6.8 System.dmg is 4.82gb (actually they both are) is this right?

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364 replies

zirkenz

Level 1

0 points

Sep 2, 2011 2:07 PM in response to Roy Miller

isn't the mac box set a genric full install of SL? If i had an original SL imac 2011, i could reinstall with the Mac Box set and end up at the same point....right?? If not that would mean that the mac box set 10.6.3 edition and the SL upgrade discs don't support quad core or 2011 mac computers or core i family.

My theory is installing via TDM via macbook perhaps the SL install thought my imac is a macbook. I mean, when the imac drive is attached to my macbook under TDM it is just a drive at that point on my iMac and not an imac. So when using the macbook to install using the mac box set/retail upgrade disc , it thinks the drive it is being installed on is a macbook one and installs the appropriate stuff or just installs a generic bootable base. The benchmark scores i'm getting seem inline with a macbook core 2 duo. What scores are u getting on the machines you downgraded vs online established stats? Is there any hope of you making a YouTube video of your procedure? Honestly, i read it ten times over and can't figure out what to do. But if both methods (yours and the one i used) result in the same geekbench scores then i guess it is pointless.

As for the partition issue, i feared that was the only solution but i have another thought and wanted to see if you all think it would work:

I boot from the external disc that is a clone of the imac now with SL 10.6.8+all updates, then insert the mac box set SL or retail SL upgrade disc and use disk utility to reformat the imac hd, then quit DU, double click the installer and install SL on the imac drive, let it boot and finish install,do the registration/set up, install updates and done. Do you think this method will install the correct drivers and stuff?

Sep 2, 2011 4:25 PM in response to zirkenz

Okay zirkenz, thanks for "making" me do a Geekbench 😉

My score with stuff open, doing the 32-bit test, is 5819... the target on their benchmark page says 5900 for my make/model. That's pretty durned close. I'll restart and try again.

Okay 5936 this time... wooohoo! (Roy, you just keep on giving!)

zirkenz

Level 1

0 points

Sep 2, 2011 4:50 PM in response to Tech Harmony

Thanks so much for the info. If the restore disc is 10.6.6 then can i boot from it? What i'd like to know if Roy's method applied to a preinstalled lion system yields low geekbench scores. If it does then it proves that downgrading SL results in a system that yields half the performance. As for Roy's method, i and someone else did ask how to do step one and never got an answer. I don't know what part is being done on what system. If i had a step by step visual guide that would be cool. i'd even be willing to pay for the privilige. Believe me i admire you geniuses who figured all this out and can decipher the instructions. I'm no tech slouch but honestly i'm ashamed to say its over my head and humbled.

If i upgrade my macbook to 10.6.8 i don't lose anything like Front Row right? I've been afraid to update it.

Sep 2, 2011 5:09 PM in response to zirkenz

Don't be ashamed. I just got used to eating humble pie.

Hey, try XBench for you scores too, just for giggles.

Yes, I think you will be able to boot from the special factory SLeo restore discs for your iMac.

As you can see from my Geekbench, my downgrade from Lion resulted in a Snow Leo machine that runs on par with the benchmarks. No problems. It's not an iMac but I believe our computers were forged in the same era. I don't want to give you false hope, but this feels like it should work, doesn't it?

10.6.8 shouldn't mess up your Macbook Pro Core2Duo but I'm skittish on such things myself... don't upgrade if you don't have to or want to. But then you will use your iMac install (ironic)... it's alright if it's slow, you just don't want it to crash on you. A free partition somewhere to create your master clone... you may only need 10GB but why not give yourself 20-30GB and worry about it later. If your goal is to get a speedy system, then it's worth some shenanigans.

I'll look back in the thread to see what you got stuck on... i can't record a video right now...

Maybe I can sum up what you need to do given your setup....or at least to start...brb

zirkenz

Level 1

0 points

Sep 6, 2011 7:34 PM in response to Tech Harmony

Tech Harmony, booting in safe mode, then running the combo updater and fixing permissions then reruning geekbemch did not work. i get the same scores. one thing did pop up in repair permissions one of the items said:

Warning: SUID File "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAg ent" has been modified nd will not be repaired

Don't know what that means but now i'm working on Roy's method but i was wondering since you already have a file that works as it should is there anyway i can download that from you? You would be literally saving me from disaster. I can provide space for the upload. I have already paid apple for 5 liscs of SL, so it would not be illegal. Sorry to be so forward and putting you in an akward situation but i'm seriously desperate.

As for the question as to why my system is partitioned into 2 is because i created a partition to install SL leaving the Lion parition intact in case my SL effort failed. Then i went to delete the lion partition, it did but i was not able to join them into one parition again. I was actualy so excited that SL had installed on one partition and booted, i literally cried. Last time i did that was when my father passed when i was 5. I was getting ready to use my clone of this parition to repartition the imac as one then restore but then i was on another forum thread about installing sl on the new 2011 mac mini and that is where the whole geekbench thing came up. I ran the test and found out that i'm only getting half the performace.I turned ghost white and was sick to my stomach. I just pray Roy's method works for me. Still have not heard back from you all on geekbench scores after using roy's method. I know tech harmony has acheived 100% success so i'm hopefull.

Again i apologise if i come across like a nutter but without getting into it, i find my self in a very desperate situation that has my head spinining.

Roy Miller Author

Level 1

32 points

Sep 7, 2011 7:35 AM in response to zirkenz

@zirkenz

I also ran the 32 bit free geekbench app and am getting half the score for this model.

what score did you get, and what score did you expect?

If you posted this already in this thread - sorry, I haven't found it.

zirkenz

Level 1

0 points

Sep 7, 2011 3:36 PM in response to Roy Miller

i got 55xx consistently, i should get 10xxx according to all the 32 bit geekbench scores posted online for my imac which is the core i7 21.5" maxed out. No i was not comparing the mac mini to the imac just saying that i learnt about geekbench and low scores from that forum and realized that i too was getting low scores. I know the mac mini has different hardware and expecting anything with SL with this sytem is expecting too much. Tech Harmony seems to have had success 100%. Roy did u run a geekbench? What are your scores? Do you think they changed something with my CTO imac?

Roy Miller Author

Level 1

32 points

Sep 8, 2011 8:44 AM in response to zirkenz

Hey Zirkenz,

no, I've never run geekbench. My challenge was to get the 2011 MacBook Pro, that was delivered with Lion installed and no install discs, configured and running Snow Leopard. We are not ready to deploy Lion systems in our environment, for several reasons. The basic reason is that we don't know enough about the Lion system and how it will intergrate into our heterogenous computing environment (Mac, Linux, and Windows, servers, laptops, and desktops, and lots of required security policies and settings).

The MacBook Pro that I ran through the retrograde process was needed to replace an older MacBook Pro that died suddenly. After successfully installing the system a couple of times, wherein I added more 3rd party applications and configured user accounts to the source image, I gave the laptop to the end user. I've had no complaints from the user, nor heard of any difficulties.

I've always been a bit suspicious of "standardized" scoring methodologies, as truly, there is no "standard" computer or individual, in my opinion. Yes, I see that one can get a warm fuzzy feeling from achieving a "normal" score, or can feel pretty uneasy if the "normal" score is not achieved.

However, I believe that computer use has much more subjectivity built into it. If the user is happy/pleased by the responsiveness, speed, and capabilities of the computer they are using, then this is a great match, regardless of how said computer scores in any evaluating system. Conversely, if the user has a feeling that the computer is slow or unresponsive, then they are likely to be unsatisfied, again irrespective of what the evaluating score for that computer is.

and, I've had the experience where the very same computer system has ellicited both responses described in the previous paragraph. One user was extremely dissatisfied, while another was very happy - both using the same computer and system.

So, my next question to you is: how does your new iMac seem to you when you use it? If the only thing bothering you now is the "low" geekbench score, then perhaps you can still profitably use the new iMac, while still trying to unravel the scoring issue.

cheers!

zirkenz

Level 1

0 points

Sep 9, 2011 2:02 PM in response to Roy Miller

hi,

still working on roy's method, so far it is still chewing me up 😁 😕 😟 but i have a few questions:

1. Can the restore disc that comes with a 2011 SL core i5 imac be used to restore the i7 since they are identical except for the upgraded processor?

2. Roy, how does your method install the correct drivers for the core i family? You said that the retail SL disc 10.6.3 lacks support for the core i family but the updaters do. So when i ran the comobo updater it should have installed the missing holes. From what i understand your method marries the retail sl 10.6.3 with the combo updater creating one super installer which you install on the imac for example and it should in theory install the right updaters. How is this different from what i did? Unless my current SL install thinks its a macbook that would explain a lot and why its not filling any holes. Would still be cool if you guys could put out a video how to.

3. If i boot of the clone of the imac now with sl+updaters and reinstall sl after paritioning the imac into one partition, does it see my bootable clone as a macbook and basically does the same thing on reinstall i.e see my imac as macbook thus putting me back right where i started?

4. Why can't you use the system restore disc to create the "roy installer"?

zirkenz

Level 1

0 points

Sep 9, 2011 4:56 PM in response to Tech Harmony

thanks for the response. I want to be clear that i am in no way trying to undermine roy's method rather i'm just trying to understand how this all works. I truly respect roy's and your intelligence, skills and advice and am profoundly grateful for all the guidance. I agree avoiding an apple store visit is a good thing which is why i will do everything i can to make this work. A friend said he would let me borrow his 2011 i5 imac restore disc, which is why i asked.

I think i got part A processing. Just got a dialog box saying something about creating an image file with just an ok button, clicked on it and it is still running. So far 2 files created a system.dmg 4.82GB and a Tempimage.sparseimage file 6.6 gb. green check marks on "customize package selection" and "add packages and post install scripts" (bottom of those windows). At the bottom of "create image" a spining disc showing its still running. it sure is taking a while.

Question i have is if i download the combo updater on a macbook or an imac does that make a difference? Meaning does the website know what mac i'm on and hands me the installer for that computer?

2 people on this forum did exactly what i did and got SL running but none of them have responded with geekbench scores.

Roy Miller Author

Level 1

32 points

Sep 9, 2011 5:10 PM in response to zirkenz

zirkenz,

I think i got part A processing. Just got a dialog box saying something about creating an image file with just an ok button, clicked on it and it is still running. So far 2 files created a system.dmg 4.82GB and a Tempimage.sparseimage file 6.6 gb. green check marks on "customize package selection" and "add packages and post install scripts" (bottom of those windows). At the bottom of "create image" a spining disc showing its still running. it sure is taking a while.

Great! it does take a lot of processing time. it took some hours (??) on my Mac Pro. However, step C is literally 5-10 minutes!

Question i have is if i download the combo updater on a macbook or an imac does that make a difference? Meaning does the website know what mac i'm on and hands me the installer for that computer?

it doesn't matter. The updaters all handle all systems, unless they specifically have a model name in the filename. you're good to go

please see my previous post about the "identical" (not!) nature of the i5 & i7 iMacs.....

good luck, I'm going home for a weekend - hooray!

thanks for the response. I want to be clear that i am in no way trying to undermine roy's method rather i'm just trying to understand how this all works.

I get it, I appreciate it, and this is one of those where they say in the movies: "Just have some faith my son! All will be revealed in time." Really, it takes going through this complicated-looking process to find out that it isn't quite as complicated as it appears. And, I'm a huge fan of "understanding how it all works" - just sometimes this gets in the way of getting things done.

good luck, please let us know how it goes for you!

Sep 9, 2011 5:17 PM in response to Roy Miller

Good show!

"many of the steps will become meaningful as you try them"

This is what happened for me. I had a hard time wrapping my mind around the big picture until I'd finally completed a run-through of this....

Sep 9, 2011 8:13 PM in response to zirkenz

Sure, you can boot off the clone... you just need a working Disk Utility and your files on a drive other than the one you're going to reformat/repartition.

System.dmg (or whatever you renamed it) is the only file you use in the actual restore step (check out the steps).

I personally kept the other files around in case I screwed up extracting System.dmg or needed to retrace my steps later. Just how I roll, out of habit.

Sep 9, 2011 8:46 PM in response to Roy Miller

So I'm running into this problem and need to get it fixed on two brand new Mac Pro's (literally bought two days ago) by Monday. Im doing a live stream event and need the software to work properly but it is buggy with Lion as of now. I tested on a Mac Pro running snow leopard and the software worked fine.

As I was brainstorming on how to solve this problem with a friend we talked about buying an additional drive to install into the tower and make it the boot up drive and install snow leopard from there with brand new snow leopard install disks. Shouldn't this work as a work around for Mac Pro users?

Thank you!

Sep 9, 2011 9:04 PM in response to Roy Miller

Mac Pro's came installed with Lion, that is correct correct.

I bought a family pack snow leopard disc brand new from a certified mac seller today. not an actual mac store. I called a mac store and know they have pulled all the discs from their retail stores. should these discs work for me?

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