According to community discussions, . This means:
To downgrade from 10.50 to 9.00, you will need to prepare the following:
The downgrade process involves corrupting the current active slot (e.g., 10.50) using hardware tools, which forces the PS4 to boot from the alternative slot, which may still hold a lower firmware version (e.g., 9.00). Step-by-Step Downgrade Procedure Phase 1: Preparation and Soldering ps4 downgrade 10.50 to 9.00
How to Revert the PS4 to a Previous Firmware (Full Tutorial)
Identify the 32 MB flash chip (NOR) and the Syscon chip. According to community discussions,
In the early days of the PS4 scene, Sony used a generic encryption key (often referred to as the "Beta Key") for the Syscon (System Controller) chip. This generic key was discovered, allowing modders to communicate with the Syscon and force the console to accept older firmware. If you own an original PS4 or a PS4 Pro, a software downgrade is technically possible via hardware modification.
Firmware 9.00 is considered the "gold standard" for homebrew because it supports a highly stable, widely used jailbreak. While newer jailbreaks (like ) have expanded compatibility up to version 11.00 and beyond, 9.00 remains popular for its ease of use. Alternatives for 10.50 Users In the early days of the PS4 scene,
The PS4 uses eFuses—tiny electronic fuses that are "blown" during firmware updates. This is a that cannot be undone. The number of blown eFuses corresponds to the minimum firmware version the console can run. If your console has blown eFuses indicating it should be on version 10.50 or higher, it will refuse to boot with any firmware version below that threshold.