According to the ConsoleMods Wiki , simply downloading an older firmware file and installing it via USB will not work; the console will throw an error. The PS4 firmware is protected by sophisticated security mechanisms, including signed firmware and a system controller (Syscon) chip that ensures you can only move forward in version numbers. The Only Exception: Hardware Revert
To write the modified data back to the console, the Syscon chip must be placed into debug mode. This requires a delicate micro-soldering technique where a single, specific pin on the Syscon chip is desoldered and physically lifted off the motherboard pad. 5. Writing and Booting ps4 downgrade 1302 to 900 top