If you are serious about PS4 modding, avoid random Google searches for "Downgrade Exe" files. Instead, rely on the established community hubs:
To downgrade, you must physically open your PS4 and use a Teensy or an Arduino to interface with the console’s and NOR flash chips. 2. The "Slot" System Ps4 Tool Downgrade V1.00 Exe Download
The "Tool" part of this process usually involves a script (often written in Python, not a standalone .exe) that patches the Syscon chips to allow the console to boot into the older firmware version. Red Flags to Watch Out For If you are serious about PS4 modding, avoid
Claims that you can go from Firmware 11.00 straight back to 1.76 instantly are false. You can usually only revert to the version you were on immediately prior to your current one. The "Slot" System The "Tool" part of this