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.
While the idea of a sounds like a quick fix for gamers wanting to unlock their consoles, the reality is far more technical. Legitimate downgrading requires soldering skills, specific hardware interfaces, and a deep understanding of the PS4's file system. Ps4 Tool Downgrade V1.00 Exe Download
The short answer is . There is no "magic" Windows executable file (.exe) that you can simply run on your PC, plug in a USB to your PS4, and click a "Downgrade" button. Claims that you can go from Firmware 11