More Leopard-taming tips tip up

BACK IN September, we ran a piece on how to install the pre-release version of Mac OS X 10.5 - " Leopard" - on unsupported Macs. Officially, 10.5 on PowerPC processors only supports Macs with a G4 processor running at 867MHz or faster - or any G5 or Intel-powered Mac, of course.

Rcently, though, an inventive Mac hacker announced an easier way.

The final, release version of Leopard was a bit less picky than the beta. While the beta checks the model of Mac to see if it's a machine that shipped with an 867MHz or better chip, the installer for the release version simply asks the Mac what speed its processor is running at - so it will install on G4s with a sufficiently fast processor upgrade card, even if they shipped with a slower chip. Some people even report G3s with G4 cards working, albeit sluggishly.

If you've got both a supported and an unsupported Mac, there's an easier way. It's only the installer which checks - once it's installed, OS X no longer cares how fast your processor is. So, either temporarily transplant the slower machine's hard disk into the faster one, install, then move it back, or set up the slower machine in Firewire Target Mode , connect it to your faster Mac, install onto the new external drive, then disconnect and reboot.

If you couldn't beg or borrow a fast enough Mac, though, it was back to hacking the installer DVD. Until now. The new hack is much simpler: you simply instruct your Mac to lie about how fast its CPU is. All that's needed is a couple of commands to the Mac's OpenFirmware - the RISC equivalent of a BIOS. It will only last until it the machine is next rebooted, but that's all you need to get the Leopard loping along.

You can get the gen from here. We haven't tried it ourselves, so if you turn your Mac into a doorstop, it's not our fault, OK?

The other kind of unsupported Leopard install that lots more people would like is, of course, to run OS X on a generic PC. It can be done - we covered it in October and there's plenty of info out there.

However, it's against Apple's licence, even if you bought your copy of OS X and own a suitable Mac, so don't. It's naughty. µ