YESSSSSSSSSSSSS!! Got it working.
Spent 24/7 on this **** for more than two weeks. And in the end, I got it working. My game has filesize and hash checks... but somehow I fooled my PS3 and the checks became null. All it takes is a certain amount of luck and little-to-medium knowledge.
Yes, you are right. If you're trying to mod a psarc, don't lose hope if it doesn't work! Just keep working on it and don't give up! Think of ideas and workarounds, etc.
**Since nobody pretty much helped me. I'm not going to explain how I hacked my psarc, but I can tell you one thing: any PSARC is hackable / runnable.
Good luck, guys...