This process requires advanced soldering skills, electronic knowledge, and the acceptance that you may permanently destroy your PS4. This article is for educational purposes. Proceed at your own risk.
The console must have a Renaissance Syscon chip (identifiable by "A0" and "-C" markings). Tools Needed: Teensy 2.0++ or similar microcontroller. USB to TTL adapter . Soldering station and high-precision soldering skills. how to downgrade ps4 9.60 to 9.00
This is the most documented method for fat and slim models. This process requires advanced soldering skills