Some "ISO" downloads are actually Android APKs packaged with an emulator, which will not run on original PSP hardware.
If the file is a (containing an EBOOT.PBP ), place it in PSP/GAME/ . subway surfers psp iso download new
: Available for download as an APK or through the Google Play Store . iOS : Available for iPhone and iPad via the Apple App Store . Some "ISO" downloads are actually Android APKs packaged