Install the latest version of the PPSSPP Emulator from the Google Play Store or the official website.
Some versions are actually highly modified versions of other PSP titles (like Syphon Filter or Resistance: Retribution ) reskinned to look and play like Resident Evil 4 . Key Features of Fan-Made ISOs Resident Evil 4 Ppsspp Iso
Use a tool like ZArchiver to extract the .iso file from the downloaded .zip or .7z archive. Install the latest version of the PPSSPP Emulator