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SkyCapt's picture
Joined: 2017 Jan 11
Booting & installing model-specific OSX discs on any (new-world) PPC Mac

They don't boot because the computer's model identifier name doesn't match an expected name that was coded on disc data. In other instances they don't boot if an Intel-only Tiger disc is attempted on a PowerPC Mac, although Leopard discs supplied with Intel Macs do work on PowerPC machines because Leopard is totally Universal-Binaries.

To make a disc/set boot, either the disc could be edited to accept the machine id, OR, the machine id can be (most temporarily) altered to reflect the id to which the disc is keyed.

Find the machine id in System Profiler, it looks like "PowerMac3,6" for a Mirror Door, or "PowerMac7,2" for a 2003 PMG5.

Next, it's best to decipher what the disc expects, otherwise you could scan "Mactracker" (v5 or later) for possible id's based on OS version number, OS build number, and on-board AHT version number. Where is that expected id located on disc?

(this section is optional, if you wanted help understanding your "grey" discs) Find the build number on disc: this is from a model-universal Tiger 10.4.0 PowerPC Install Disc. Use the awesome "Property List Editor" program to open and decode the disc file named "System/Library/CoreServices/SystemVersion.plist", expand the Root hierarchy, and there it is, 8A428 build number (this particular disc for example). Property List Editor comes inside Developer Tools, I should dedicate a page to PLE...


MikeTomTom's picture
Joined: 2009 Dec 7

For me, I prefer to edit the "grey" discs to suit, if needed. So that if I ever need to reinstall that OS to the same machine, it's already prepared, ready to go.

I had recently discovered that a Mac mini core 2 duo I own (shipped with Leopard), had originally shipped with Tiger 10.4.10 - I had got mine near the end of it's production range, so it arrived with the newer OS.

Having never owned or used a Mac with an Intel version of Tiger I was keen to see what it was like compared to the PPC version. At the MG we didn't have a copy of the Mac mini original, but we do have a MacBook Pro install set for 10.4.10, so this is what I worked with.

The workaround for using the 10.4.10 grey disks is almost ridiculously easy.

I found the clue for it on this insanelymac forum page.

I needed the disk read/write, which it already was (I had written the image to a USB stick so as not to waste a DL DVD), then using a plain text editor, edit the file named "OSInstall.dist" located inside "OSInstall.mpkg" (inside of the System folder on the stick).

I used a slightly different approach to the example given on that page. All I had to change was any instance of the term "Macbookpro3,1" to "Macmini2,1" and save. - The method outlined on that page would create a universal install. - I just wanted it for the mini, so effectively I created another "grey" just for the mini.

Changing the Mac identifier name in a grey install disk to that of the target Mac worked very well (given a compatible OS version) and installing Tiger onto the Mac mini went smoothly.

SkyCapt's picture
Joined: 2017 Jan 11

Example, I have physical oem disc set 10.5.0 keyed to Intel "iMac7,1" and I can boot/install it on my PPC PowerMac3,6 - also I can run less-encompassing installers from the discs, using my existing Tiger OS if-i-want, installers like iLife'08/2007 that's found on this disc set & also whose installer got keyed to "iMac7,1".

I think doing this is not risky, that the majority of discs and hardware models will interchange without issue, or some with minor device-driver issues that might be easy to identify or repair.

To use Open Firmware to change hardware id into that of the disc: break into Open Firmware mode while beginning to boot the Install Disc; these are the firmware commands (thanx to a guy on macrumors & other hackers)

dev /

This ".properties" displays output in what you should see your existing model id name, twice, at the top two lines of text output. ".properties" can be commanded again later, to confirm your editing skills.

Because my example is booting an iMac7,1 disc, that's what im writing below, you'd have to obviously substitute your disc's target-id :

" iMac7,1" encode-string " model" property

// the above firmware cmd needs this exact syntax, involving quotes and whitespace following every open-quote. This cmd sets line-one in the properties output. Next, you could save some typing by pressing up-arrow to duplicate this cmd and use backspace to morph this cmd into this next cmd:

" iMac7,1" encode-string " MacRISC2" encode-string encode+ " MacRISC" encode-string encode+ " Power Macintosh" encode-string encode+ " compatible" property

// That last cmd replicates lines 2,3,4,5 for the new id. You could issue the ".properties" command again, to verify lines one and two reflect {iMac7,1} and lines 3,4,5 remain the same.

Type "bye" or "mac-boot" to leave firmware mode and thus continuing to boot the Install Disc. The machine-id edit only takes hold for the one boot session, so it's safe in that just restarting can return system to normal, and the one-boot-limit is all that's needed to load and install from disc.

SkyCapt's picture
Joined: 2017 Jan 11

I just installed the G5-specific OSX 10.2.7 on my Mirror Door 2003 (a 'closet' G5 motherboard) by tricking the "PowerMac7,2" machine id. This is the OS+hardware configuration named "Smeagol" not Jaguar. It says "(G5)" in About This Mac, running on G4 CPU. And Apple's CHUD software v3.0.0 & v3.0.1 both report "Smeagol" for this os class/type.

Exceptionally fast and smooth drawing/animation, even without disabling any port extensions. It comes with QT 6.3 and any updater to QT is spoiling this great video generator. QT 6.3 also draws better than QT 6.4-6.5 on my 10.2.8 G4 OS.

Smeagol looks so great for gaming and classic mode. I played some of my most demanding 3D games: Rayman 3, Indiana Jones Emperor's Tomb, American McGee's Alice, Tomb Raider (IV) the Last Revelation in Classicmode, all wicked.

10.2.7 has USB2 support (unlike 10.2.6) and the G5-specific 10.2.8 update installs without a trick, as if it looks for build-number instead of machine-id. The 10.2.7 plays even more psycho than 10.2.8 and there is no G4 equivalent of the 10.2.7 - this is fun.

Compared to 10.2.8, 10.2.7 doesn't have the latest jagtech. I could import 10.2.8's ATI extensions & OpenGL framework back into 10.2.7, but I'll wait to see what's necessary...

SkyCapt's picture
Joined: 2017 Jan 11

This keeps getting crazier. I'm booting respectable Tiger OSX 10.4.8 now with my Mirror Door '03 model but I falsified its machine-id "PowerMac7,2" (G5). It does the same video generator on-steroids that OSX 10.2.7 has! I can switch back to my regular "PowerMac3,6" G4 machine-id and compare it to my previous now-disappointing video generator.

I made the counterfeit machine-id semipermanent so I don't need to type anything when restarting. This so badly shouldn't be working, that it can be said this MUST have been programmed to work this way. To demonstrate, if I run my AHT software on this G4 with the G5 machine-id set, nothing works right. But on the other hand, OSX stays fully functional, and the id G4 versus G5 behaves like a toggle switch between G4-video & G5-video.


SkyCapt's picture
Joined: 2017 Jan 11

Why did this happen on April 1st the irony?
It's so big, it has gotten its own new forum topic