The premise behind the search term "God of War 4 PPSSPP ISO" is technically impossible. Therefore, there is no legitimate "fix" for an ISO file that does not exist.
If your goal is to play the 2018 game on a non-console device, consider these official methods: PC Version : Purchase the official PC port available on Epic Games Store Cloud Gaming : Use services like PlayStation Plus to stream the game to a compatible PC or handheld device. optimize settings god of war 4 ppsspp iso file download fix