Ps4 Downgrade 10.50 To 9.00 [better] -

You must modify the Syscon dump to reset the "minimum version" counter from 0xA (10.50) back to 0x9 (9.00). This requires hexadecimal editing.

Unlike some older consoles or specific circumstances involving factory resets, a standard update file cannot roll the system back. The PS4 checks the version number in its "NOR Flash" memory. If the version in the NOR says 10.50, the system will refuse to boot an operating system lower than that. ps4 downgrade 10.50 to 9.00

If you find a "software downgrader" for 10.50 → 9.00, it is either malware that will encrypt your PC or a tool that will corrupt your hard drive. Sony’s security chain is cryptographically locked. No software exploit can bypass the fuses. You must modify the Syscon dump to reset

A persistent rumor in the scene claims a developer is working on a "Downporter"—a software tool that patches the eFuse check in RAM, allowing a 9.00 installation. The PS4 checks the version number in its "NOR Flash" memory

If your PS4 was specifically on version 9.00 immediately before you updated to 10.50, that 9.00 data still exists inside your console's flash memory (sflash). To access it, you must perform a hardware revert. Requirements for the Hardware Revert