How to mod GI Joe - Xbox 360
1) I found it the easiest to... extract the file 'GIJOE_25' from your save file.
2) Open the file 'GIJOE_25' (that you extracted from the save file) in any Hex Editor.
3) Then look at the image below for the mappings to...
-Battle Points
-Unlock Characters
-Unlock Missions/Stages
4) Make any changes that you want, then save the file.
5) Then inject the file 'GIJOE_25' (that you just extracted and edited) back into your save file (overwrite the one in there).
6) Now rehash your save file, and you're done!
Credit Goes to JizzaBeez