Kane Adams Posted December 9, 2007 Share Posted December 9, 2007 Dylan McDermond - 2007.12.06 Editor's note: Every Mac and Macintosh clone with PCI architecture supports Open Firmware, so this technique should work with any Mac that could possibly run Leopard. It completely eliminates the need to hack the installer on the Mac OS X 10.5 installer DVD. dk I have found that, by far, the easiest way to install Leopard on unsupported G4s is to spoof the clock speed in Open Firmware before installing. Spoofing will have Open Firmware tell OS X that your G4 is up-to-speed until you reboot. This will allow you to install without hacking an install disc or working in Target Disk Mode. You will still need to meet the 512 MB of RAM requirement, but I wouldn't suggest using less anyway. Without further delay, here are some instructions I have passed on to a few friends already: To install Leopard on an "unsupported" G4 clocked under 867 MHz: 1. Reboot your Mac and hold down the Cmd-Opt-O-F keys until you get a white screen with black text. This is the Open Firmware prompt. 2. Insert the Mac OS X Leopard Install DVD. 3. Type the following lines exactly as shown below into the Open Firmware prompt. Be mindful of capitalization, spaces, zeros, etc. If the command is properly typed and understood, Open Firmware will display "ok" at the end of each line after you hit "return". What these lines do is set the CPU speed reported by Open Firmware to OS X as an 867 MHz G4 processor system. They then continue the boot from the DVD drive. For single CPUs, use the following three lines: dev /cpus/PowerPC,G4@0 d# 867000000 encode-int " clock-frequency" property boot cd:,\\:tbxi For dual CPUs, use the following five lines: dev /cpus/PowerPC,G4@0 d# 867000000 encode-int " clock-frequency" property dev /cpus/PowerPC,G4@1 d# 867000000 encode-int " clock-frequency" property boot cd:,\\:tbxi 4. Continue the install normally. 5. This CPU setting is only in effect until the Mac reboots. Once OS X Leopard is installed and your Mac has rebooted, the proper CPU speed should once again be displayed when you select About This Mac under the Apple menu. LEM Found here. Link to comment https://www.insanelymac.com/forum/topic/75447-faking-out-the-leopard-installer-with-open-firmware/ Share on other sites More sharing options...
Headrush69 Posted December 9, 2007 Share Posted December 9, 2007 Nice find, I'll try that on my Dual G4 tomorrow. Link to comment https://www.insanelymac.com/forum/topic/75447-faking-out-the-leopard-installer-with-open-firmware/#findComment-532760 Share on other sites More sharing options...
Kane Adams Posted December 9, 2007 Author Share Posted December 9, 2007 if you read some more at the web site he says about "Using Open Firmware to Install Leopard below 867 MHz, The Mac Elite. Includes info on writing Open Firmware commands to a text file so you don't have to type them in" Link to comment https://www.insanelymac.com/forum/topic/75447-faking-out-the-leopard-installer-with-open-firmware/#findComment-532765 Share on other sites More sharing options...
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