Ps4 Downgrade Tool <PREMIUM — HANDBOOK>
Even before the fuses, the PS4’s boot ROM performs a minimum version check. Each game disc and system update comes with a minimum required firmware. You cannot install a firmware older than the one that was pre-installed on your motherboard at the factory.
To understand why a simple "downgrade tool" doesn’t exist (the way it did for the PS3 or PSP), you must understand Sony’s security architecture. ps4 downgrade tool
Can you downgrade your PlayStation 4 firmware to an older version? The short answer is Even before the fuses, the PS4’s boot ROM