The original repo of mmjoy_en has been archived and quite outdated in 2019. Heres an updated version as the newer infos are scattered in the forum.
This is an English translation of MMjoy2 introduction course. To start with MMJoy2 proceed to the updated wiki.
In order to download the firmware and software archive, please go to This translated page of the project. The two currently recommended versions to use with is [v20151118] and [v20160818upd1].
You can still download an outdated build [v20151118] from this outdated section from the original mmjoy repo.