I own a MacMini (Late 2006, Model-ID Macmini1,1) which originally had a 1.83 GHz CoreDuo (T2400) CPU.
Encouraged by several upgrade reports (e.g. @fixit.com) I upgraded the Mini to a 2.16 GHz Core2Duo (T7400) CPU
and it works so far without any problems in 64bit mode, albeit with a 32bit kernel.
I tried to switch to a 64bit kernel with 'sudo systemsetup -setkernelbootarchitecture x86_64', but the kernel still
boots with 32bit version.
Not really a problem, but do I have a problem running Lion? I made the upgrade exactly for the new OS!
I found (with 'ioreg -l -p IODeviceTree | grep firmware-abi') that this mini has a 32bit EFI and now I want to know:
Does LION need a 64bit CPU or a 64bit CPU *and* a 64bit EFI?
Thank's for your replies - Matthew
Just did this and it seems to have worked perfectly.
0. Installed a 64bit CPU (Core 2 Duo 2.16GHz) in the 2006 Mini.
1. Made a Lion install thumb drive.
2. Booted the Mini in Target Disk Mode (hold "t" key on boot).
3. Connected a FW400 to FW800 cable to Mini and a 2009 MacBook (MacBookPro5,3).
4. Booted MacBook with "option" (alt) key.
5. Selected the Mini's drive for boot.
6. Ran "Install Mac OS X Lion" from thumb drive.
7. After the reboot, renamed /System/Library/CoreServices/PlatformSupport.plist to PlatformSupport.plist.JustKidding
8. Shutdown both machines.
9. Unplugged FireWire and booted Mini. Saw the "question mark folder" for a moment, and then it booted Lion.
To be clear, this allowed me to upgrade my existing Snow Leopard install on my 2006 Mini -- with an aftermarket 2.16GHz Core 2 Duo -- with 32bit EFI. Boots right up. No bootloaders or cloning needed.