MX4SIO (Memory eXpansion For SIO) is an adapter for the PlayStation2 that lets you connect TF/SDcards to the memory card slot.

https://retroscalerretroscaler.aliexpress.com/store/group/For-MX4SIO-SIO2SD-Card-adapter-series/910322130_40000000747107.html?spm=a2g0o.detail.0.0.5c8f3964YWXvFB
  1. How to Make the Game Card for MX4SIO Adapter?

MX4SIO adapter can’t accept all PS2 games, please consult the OPL game compatibility list. Can check it in the link here:

https://docs.google.com/spreadsheets/d/1zHxhwT4nSkrCCAqJNlSndw1Yeh_9g3eL/edit?pli=1#gid=669997000

Please use the FMCB which has the latest version OPL v1.2.0-Beta-1828-b47f7db to start the MX4SIO adapter . You can download it from the address below:

https://github.com/ps2homebrew/Open-PS2-Loader/releases

  1. How to Upgrade the OPL of the FMCB ?

2.2 The video of Upgrading the OPL