The Modbo 4.0 is one of the most popular modchips for the Sony PlayStation 2. It’s a clone of the original Matrix Infinity range of modchips.
It provides full region unlocking and backup booting of both PlayStation 1 and PlayStation 2 games, as well as the ability to run homebrew from the DVD drive.
The Modbo 4.0 is compatible with all versions of PlayStation 2, however it requires soldering no less than 20 wires to various surface mount components. It is not recommended to attempt installing this if you are not a confident solderer.