lipsum has shared an EBOOT modification for P4G that allows custom files to be loaded from a new CPK. Similar to P5′s mod loader, the new mod.cpk archive has priority over the game’s original data.cpk– which means that you don’t need to repack and compress nearly 2 GB of data every time you test a mod!
You can download the source here, which includes a readme with instructions on how to patch your own EBOOT. At the moment, it’s recommended to use this temporary version of the Mod Compendium to create mod.cpk files for P4G.
The same developer also recently created io_plg, a blender import/export plugin for Atlus’s PLG (vector image) format.
In other news, p5cutintool has been updated to support repacking as well as unpacking custom DDS cutins for conversations in P5! An editor for P5′s FTD tables has also been released by a community member.