A true, official version of Resident Evil 4 was never released for the PlayStation Portable (PSP) [5, 6]. Because of this, any "highly compressed ISO" found online is typically one of three things: a fan-made mod, a port of a mobile version, or a scam. The Backstory of the "PSP Port"

• PSP Firmware: 3.40 or higher
• PSP Model: Any PSP model (PSP-1000, PSP-2000, PSP-3000)

Conclusion

Please note that this download is provided for educational and entertainment purposes only. The compressed ISO file is copyrighted by Capcom, and we do not claim ownership or rights to the game. Users are expected to comply with copyright laws and regulations.