How Difficult Would It Be To Make A Modding Addon?

It was already made for ashita, but there was an issue where the game uses 2 different function calls for loading files and atom0s was having some difficulty getting it to work for both at once. I'm not sure exactly what the problem was since I didn't work on it, but it is probably non-trivial.

I would think it's just a matter of hooking both, but I'm sure he would've tried that, so likely something else going on.

wooot PSO!

As far as I'm aware you'd have to do this at the plugin level. Addons won't have access to a low enough level to install a detour on the functions that load DATs.