To the best of my knowledge it is impossible to edit the original PlayStation disc. People have copied the contents to a PC, made edits and then burned a new disk. In effect this is a bootleg disk and I believe the keyhash needs to be modified in order to play it on line. In order for others to play the same mods they would need a similar counterfeit disk. I have not tried any of this myself, not just because of the legal implications but If I’m going to do all that work, why not use the PC version instead? It’s easier, gives much better results and it’s legal.