As the impending release of OSX 10.8 Mountain Lion is near, it is also time to make sure that we are ready to install Apple’s new OS onto our custom Intel hardware. We will cover the in-place upgrade from OSX Lion 10.7.4 to the GM(Final) release of OSX Mountain Lion.

This procedure has been confirmed to work with the official release of Mountain Lion in the App Store.

A clean install of Mountain Lion will not be covered in this article, but you can refer to this site which will walk you through a clean install. A clean install is great if you want to start from scratch, but for the rest of us with a lot of data, read on.

Tonymacx86 has released Unibeast for Mountain Lion which can be used to perform a clean install.