That PRX has nothing to do with ISO loading right now. Right now, ISO loading is totally separate from that PRX. Currently, ISO loaders trick the PSP into thinking the ISO is the files on the UMD. Once hackers start cracking that PRX (It's only been on 3.50 and 3.51), we can have faster ISO loading and less battery drainage.
vettefan88 is trying to figure out a way for us to just load the IMG file from the memory stick so we don't have to compile the ISO each time.