How to disable Windows 8.1 driver signature verification?

Question

Windows

Good afternoon. I can't go into Windows diagnostic mode to disable driver signature verification.
With Shift + Shutdown pressed - only the option to turn off the PC.
I enter through the console: bcdedit / set "{current}" bootmenupolicy legacy , I get: "Unable to open configuration data. The specified file cannot be found."
in msconfig, the "boot" tab is empty and cannot be edited.

Answer 1

Everything is described here