The Syscon (System Controller) chip is a Renesas RL78/G13 microcontroller that oversees many of the console's low-level functions. By dumping the Syscon memory and flash memory of a specific PS4 console, one can update the system software to any version and subsequently restore these dumps to revert to an older firmware.
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: Using a microcontroller like a Teensy or Arduino to "glitch" the Syscon chip.
Note: This requires advanced micro-soldering skills. If you damage the Syscon or NOR beyond repair, your PS4 is permanently bricked .
The technician extracts the current data (the "dump") from both chips to a computer.
Sony has designed the PS4’s boot chain with an (electronic fuse) system. Here’s how it works:
Each individual PS4 possesses unique, per-console encryption keys. This architectural decision ensures that a downgrade method that works on one console cannot be universally applied to all others. Generic downgrade solutions are therefore impossible to create without factoring in the unique keys of each specific machine.
Insert a USB drive containing the official (the larger installation file, not the standard update file) of the target lower firmware. Allow the PS4 to initialize and complete the installation. Is Your PS4 Eligible for a Downgrade?
Using a hardware SPI programmer (like Teensy 2.0++ or Raspberry Pi Pico) to directly read and write the NOR chip. This requires: