To perform a firmware revert, you need specific hardware to interface with the console's chips. The most reliable and widely used tools are: Teensy++ 2.0

No. Firmware 10.50 patched the kernel exploit used for hardware downgrade setups. Only Syscon flashing works, and no repack can automate that.

Many sites promise a "PS4 Downgrade Tool Repack" that claim to work via USB without hardware mods. These are almost always scams or malware. A software-only downgrade is technically impossible on current official firmwares.