Alright, it seems like very little progress has been seen to the completion of a patch. I also doubt that a patch will suffice to get this game running.
As it stands the problem with this game doesn't seem to be security checks, but rather files that are present in the 6.20 OFW and not the 5.00 M33/5.50 GEN. The lack of these files causes the game to lock upon the need to access one or more of said files.
Now I have a decent understanding of how the PSP works on the software end but I am unclear as to whether or not we can somehow determine which files are needed. Then possibly use them to make an "enabler" so to speak. Somewhat like the homebrew enablers that allow 1.50 kernel homebrew to be loaded on a slim without the kernel.
Probably will take a good amount of time for such a project, but if we can get the Japanese release working then the same answer should work for the USA release with a few tweaks, shouldn't it?
Let me know if this is a plausible answer to our collective dilemma, kinda just ranting