There are two things that prevent 10.8 from installing on a MacPro 1,1.
The first is the lack of EFI64. Mountain Lion as has no support for 32bit kernel and extensions so it will not boot. This is true of many early Intel macs.
The other thing is that checks are made by the installer; against a supported machines list. If your mac isn’t on the list, it refuses to install.
It’s important to note that an upgraded graphics card is virtually essential. The stock 7300 GT isn’t supported and will cause Kernel Pannic. I don’t think the X1900-xt is either, my 8800GT did odd things on DP1 but may be OK on newer builds. Ideally Id try and source a HD5770 or other newer card. Some people use PC cards and flash them Look Here for info on that, me personally, I use an official Apple HD5770. There may be fixes for the old cards but they will probably break every time you software update so go get a new card. It’s cheaper than a new Mac
The first issue can be dealt with by using the Chameleon bootloader. Chameleon will emulate EFI64 and therefore load 10.8. Chameleon has to be booted by your Mac as if it were Windows. Apple calls this BIOS emulation “Legacy Boot”. Legacy boot will only boot from internal connectors like the SATA, so no USB or Firewire drives.
My solution requires a spare HDD in addition to the drive that your OS is on, you may be able to do it all with one, but I’m not going to cover that just yet. at the end of the process you will have a dedicated boot/install drive and a dedicated Mac OS drive. This drive and the one OSX resides on cannot be an external or connected to the ODD SATA ports. It must be on the IDE cable or one fo the four SATA sleds.
I am using a cheap 8 Gig SSD that I got from ebay with a SATA to IDE converter on, and its hidden away under the optical drive so you don’t loose any HDD bays
First download 10.8 From the app store. (you will need to do this on a supported mac) and Xcode from Apple. Then grab Chameleon-2.1svn-r1921 (google for it first). or here if you must Chameleon21_r1921 Please try elsewhere first as my bandwidth provider may get stroppy with me if it gets to hammered.
Go into disk utility and partition your spare HDD. Click the options button and chose Master Boot Record. Chose two partitions, the first 1GB (named BOOT) and the second can use the remainder of the disk (named Installer). Both partitions are formatted Mac OS Extended Journaled.
Once you’ve done this you can run the Chameleon installer.
At this point you must click Change Install Location.
Select Your BOOT partition you created earlier, then click continue.
Click customize here and choose Standard under the Chameleon Bootloader package. Nothing else is needed from the installer.
Next you will need to bless the BOOT partition.
In terminal run sudo bless --folder /Volumes/BOOT --file /Volumes/BOOT/boot --setBoot --legacy
Make sure it goes in as one line, sometimes copying and pasting puts a carriage return in the middle. Also this command can only be performed whilst booted from EFI32 (so in 10.7 or from a 10.7 installer DVD/USB)
Here is my Extra Folder. Download it (place in the root of BOOT). Inside the Extra folder the smbios.plist and org.chameleon.Boot.plist files need editing. Add your serial to the SMBIOS.plist and in org.chamleleon.boot.plist set the <key>default partition</key> to <string>0,2</string> which is the installer partition.
The dsdt.aml file has an addition in it specifically to enable HDMI audio out on the mini displayport of my HD5770. If you search this forum thread there is a few posted you can try. http://forum.netkas.org/index.php/topic,1123.0.html . Edit
Now to the installer.
Locate your 10.8 installer. Right-click and chose ‘show package contents’. Locate InstallESD.DMG in the SharedSupport folder. Double ckick on InstallESD.DMG to mount it. see here http://www.youtube.com/watch?v=oPxjJcNX-xQ
Open terminal and navigate to the Mac OS Install ESD drive. cd /Volumes/Mac\ OS\ X\ Install\ ESD/ should do it.
Still in terminal, you need to mount the hidden BaseSystem.DMG type open BaseSystem.DMG and hit enter.
See Here http://www.youtube.com/watch?v=r95rirXCPAo
Now open Disk utility. Click on BaseSystem.DMG on the left, then click restore, then drag your installer partition into the destination field.
Click Restore. This will put everything but the packages and kernel on the installer partition. (You may need to rename your installer partition back to “installer” as it may now be called MacOS BaseSystem.)
Next job is to copy mach_kernel from MacOSInstallESD to the Installer partition.
In terminal navigate to the Installer ESD with: cd /Volumes/Mac\ OS\ X\ Install\ ESD then copy mach_kernel to the installer partition with cp mach_kernel /Volumes/Installer/mach_kernel have a quick look in terminal to see that it’s there with: cd /Volumes/Installer/ then ls . You should see it there.
Or watch this video
Now in your installer partition there is a system folder, and in that is an installation folder, in there is a packages symlink. delete it and the copy the packages folder from the MAC OS Install ESD.
Finally you need to open OSinstall.mpkg with flat package editor which is part of the XCode install.
Drag Distribution to your desktop and open it in text edit.
See This Video make sure you watch it in HD so you can read the text.
Pretty close to the start is a section headed var PlatformSupportValues there is a list of board IDs in speech-marks and separated with commas. like “Mac-F42D88C8″,”Mac-F2218EA9″,”Mac-F42D86A9″ you need to add your mac’s board it to it. This is specified in the smbios.plist in the Extra as Mac-F4208DC8 so if you’re using that smbios.plist then add that value. close text edit and go back to flat package editor. delete distribution from the package and then drag the one you edited from desktop into flat package editor, then save the package. this is mine with my board ID Mac-F4208DC8 and Mac-F4208DA9 OSInstall.mpkg
As an experiment I have removed what I think is the board check from this NoBoardCheckOSInstall.mpkg if you’re brave, give it a go.
Before you continue any further I warn you that this may totally screw your computer. Even if you follow the instuctions to the letter, I may have made a mistake. Back up everything and have a spare Lion install to hand. Good Luck!
Now re-boot and hold down option to bring up the list of drives, choose boot, then franticly tap the up or down arrow key until the Chameleon list of bootable drives appears. Chose installer and you’re off. it should look like a normal mac os install from there on in.
The disk with osx on should be guid partition scheme, if it isn’t installer complains.
When the installer has completed chameleon will keep trying to boot installer so edit org.chamleleon.boot.plist set the <key>default partition <string> to your Mountain Lion partition. It will probably be 1,2 or 2,2.
After install had completed I used nano, in terminal to create an “fstab” file in /etc. This has two entries in it which stop boot and Installer mounting when OSX boots so they dont apper in finder.
The entries look like this for each Partition you want to hide: UUID=39C933A6-E5A4-3CFB-8841-21C89B0EDF77 none hfs rw,noauto change UUID to the appropriate one. The UUID of a partition can be found in system report under Serial ATA.
See this video..
This is my solution for the Chameleon/Installer drive. It’s a cheap 8GB SATA SSD on an SATA to PATA adapter, hidden away under the optival drive.
I’ll keep updating as people ask questions and when Mountain Lion is released I will update further.
There is a fix for messages here http://www.insanelymac.com/forum/topic/285102-imessage-not-working-icloudinternet-etc-working-changed-bootplist-file-and-networkplist-file-help/page__st__260#entry1882700
Here are the files you need messagesfix Don’t forget to update chameleon first. If you add the module without updating chameleon you will have no boot.
Also I take no credit for working any of this out. Most of it came from posts on http://forum.netkas.org/index.php/topic,1123.0.html
Mac Rumors Forum thread
and the rest I stumbled across on the internet. If any of this is your work, Thanks!