As a Version 3.0 revision, it contains bug fixes and stability improvements over earlier 1.x or 2.x versions (like the launch SCPH-1002).
In earlier models (like the 1002), the laser assembly was placed too close to the hot power supply, causing the plastic sled to warp and skip. In the 5502, Sony moved the drive to the right side, largely fixing the infamous "flip your PlayStation upside down to play" era. Port Removal: playstation scph5502 v30 europe bios scph5502bin google
In the emulator settings, navigate to "BIOS" or "Paths" and select the file. As a Version 3