IT security researcher and reverse engineering expert stacksmashing has released an open source piece of hardware with matching software that allows two or more genuine GameBoy consoles to play competitive Tetris over the Internet.
stacksmashing began with an analysis of the data sent between two genuine hardware GameBoy consoles, and from there built a small custom PCB that attaches to a Raspberry Pi Pico. The custom PCB includes a header for the original GameBoy link cable, as well as a second header for the GameBoy Pocket, GameBoy Color, and GameBoy Advance. The Rasbperry Pi Pico loads a small piece of firmware that enables connecting of the whole setup over USB to your PC via a custom front end.
From your PC, connect to the online server (host one yourself if you like), and it will talk to your GameBoy. Invite a friend to connect with a matching code, and begin playing head to head over the Internet. The software even enables more than one person to connect, resulting in a multiplayer Tetris battle royale.
stacksmashing is selling the custom board on their online store: http://gum.co/gb-link
You’ll also need a Raspberry Pi Pico: https://amzn.to/3osiv0L
…and of course you’ll need a GB/GBC/GBA link cable to connect your handheld to this kit.
All of the software required is open source on GitHub:
With dozens more games that support the link cable, fingers crossed that more titles can be supported by the community over time.