Hello All,
I have decided to write this tutorial, mostly because i have seen a few Fan Boys writing that it is Hardware that is stopping Apple from supporting the new Mountain Lion 10.8. Which when i said it was apple getting people to upgrade and spend £2000 on a new pc i was immediately in a Flame War.
This is a Do-It-Yourself Tutorial, i will not post links to the full DMG as this is ILLEGAL, you will have to obtain the DVD from apple and pay for the Apple Developer Licence.
Anyway this will require you to burn the final DMG file to DVD as using the app gives you an error telling you the file has been modified and you must re-download 
If anyone has any solutions please let me know and i will update.
I have been at this solidly for the past 24 Hours, The problem being is that i am constantly getting the No Entry Symbol. Now i have pinned this down to the boot.efi file on the DMG.
I can get the installation to boot however the OS would not boot once the installation is finished.
I have only installed this on an MacPro1,1 however i don’t see any reason why it shouldn’t run on any of the other devices, possibly the video drivers, which can be installed later. When creating these files i have used all the strings from the Lion DVD, so anything on Lion should be supported on this!
NOTE: I think Apple has removed some drivers from this install my 7300 GT is now no longer supported. I will look into this further to see if i can bring the kexts for the older graphics from the Lion Install!
Anyway here goes!
- You will need to download the DMG file from https://developer.apple.com/devcenter/mac/index.action you will need to pay for a Mac Developer account which costs $99 a year.
- Mount the DMG that you have downloaded, inside the DMG there is a file called Install OS X Mountain Lion Preview 1.app Right click on the App and show Package Contents.
- You will want to go into the folder called SharedSupport and copy the file InstallESD.dmg and copy it to your Desktop.
- Close all the open windows, Now you will need to go into the terminal (Application/Utilities/Terminal), we are going to copy the DMG and make it writable so we can replace a file in the InstallESD.dmg image.
- Once in termal type “cd Desktop” then type in ”hdiutil convert InstallESD.dmg -format UDRW -o InstallESDedited.dmg” This will create a new file on the desktop called InstallESDedited.dmg.
- You will now want to Double click on the newly created InstallESDedited.dmg and it will now mount an Drive called “Mac OS X Install ESD”.
- You are going to have to replace the System Folder in the Drive, this contains the EFI64 boot.efi and the compatible boot files. I have a EFI32 boot.efi and the compatible files from the Lion 10.7 System Folder. Here is the link to download: System.zip.
- Drag the System File thats on the drive into the recycle bin and unzip(if it isn’t already) the downloaded System folder and copy it onto the root of the drive.
- Now open up the “Packages” folder from the root. Inside this folder there will be a quite a few items in the folder, The only one we are concerned with is OSInstall.mpkg (There is also an OSInstall.pkg BE CAREFUL). We now want to drag this file into the trash folder. Download the patched versions OSInstall.mpkg & EFI32.pkg(Right Click on Link, Download Linked File As).
- Drag the Newly Downloaded files into the Packages Directory. The directory should now look like this:
- Now you want to burn the DVDusing Disk Utility (You can also restore the DMG to a USB Flash Drive, which also works), i am sure you already know how to do this but just in case, run DiskUtility (utilities/DiskUtility) on the left hand side you should see the InstallESDedited.dmg file Click on the file then Click Burn! (Remember to put a blank DVD in
)
- Load into the Mac Pro and Enjoy, NOTE: Installation takes a lot longer than displayed, this is due to it thinking its being installed from a Faster HDD! If installed from the USB Stick then is quite a bit quicker.
Here is the Final Screenshot from my MacPro!
If you see any mistakes please leave me a comment and i will get it sorted, this includes my English!
Hope you enjoy your new MacPro Experience!
Disclaimer:
Please Take a FULL BACKUP of you mac BEFORE installing this. I will not be held responsible for any data loss, bricking etc. Basically KNOW WHAT YOU ARE DOING! This tutorial is given to you and you use at your own risk. May i stress again take a FULL BACKUP before continuing, either with CarbonCopyCloner or Time Machine.
If you are referencing this tutorial Please add a link back to my blog. This has been quite a lot of work to make this is all i ask!
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