You can only revert to the immediate previous firmware that was installed on that specific console. If your console went from 9.00 straight to 11.00, you can go back to 9.00. If your console went from 10.00 to 11.00, you cannot skip backward to 9.00.
Over the years, many ideas for downgrading have been proven ineffective. It's useful to know what work:
Sony’s security architecture uses a secure bootloader and cryptographic keys to prevent the console from accepting older software. If a website or video claims you can download a file named "PS4 Downgrade Tool v1.00" onto a USB drive, plug it into a retail console, and downgrade instantly, it is fake. These files usually contain malware, ransomware, or survey scams. How PS4 Downgrading Actually Works (The Hardware Method) ps4 tool downgrade v1.00
Sites promise the download link only after you complete a data-harvesting survey.
The Ultimate Guide to PS4 Tool Downgrade v1.00: Reality, Risks, and Safe Alternatives You can only revert to the immediate previous
When the console installs a firmware update, it checks the internal version token stored securely inside the Syscon non-volatile storage (NVRAM). If a user attempts to install an older system update via a USB drive, the Syscon identifies the lower version number and rejects the installation before execution begins. Encrypted Storage and Keys
If you aren't looking to jailbreak but simply want to play an older version of a specific game (e.g., to use a patched glitch), tools like RewindPS4 allow you to download older game versions without modifying your system firmware. Over the years, many ideas for downgrading have
Summary
The PS4 storage drive utilizes per-console encryption bound directly to the main Accelerated Processing Unit (APU) and the motherboard. You cannot slide a hard drive containing an older firmware version into another console. The system will immediately recognize the mismatch, prompt a drive format request, and install the latest system software available. Analyzing "PS4 Tool Downgrade v1.00" Software Claims
No. There is no purely software-based "v1.00 tool" that you can install on a standard, unmodded PS4 to downgrade its firmware.