Halo 1 XBOX version 4 screen split campaign exists. Of course, coop is also possible with system link.
However, this file is only available in the USA version. I am Korean. Can you make it in KOR version?
I think you can use the HEX editor, but I do not know how.
Can you help me?

https://1drv.ms/u/s!AjWnwh89CjGthGe5rEeDpeGi3mGi ← Halo (ENG Xbe=Coop Files, KOR Xbe = Nomal Files)