Probably safe to mention right now that I'm a mac user. I can still run most Windows apps through a compatibility layer, but if there's a native way, I'd rather go with that.
So, I've previously dealt only with NES/SNES/Game Boy/Wonderswan games when it comes to hacking, and with a hex editor and a brute-force approach, I've always managed. It's just one file I'm editing, and the changes I make can be instantly seen by running them on an emulator.
With PSX though, I can get the ISO, mount it, and have read
access to all the files. I can view the individual files, but because it's a CD ROM image, writing is forbidden.
My intuition tells me that I should copy all the files to my hard drive and edit them, but then I won't be able to run them on an emulator anymore(?). The ones I've used have only "Open Image file" or "Boot from CD" options.
So far the only even remotely reasonable way I can think of is editing the ISO file itself (like a SNES ROM), but although the changes I make are instant, I lose the luxury of a file directory thus having to keep track of offsets and pointers.
Is there some trick that gives me write access to mounted Images or an emulator that allows booting from a folder?