Windows 10 - Cannot disable signed driver installation

I am sick of trying to disable "only signed driver" installation on Windows 10.

I tried running as admin:

bcdedit /set testsigning onbcdedit /set nointegritychecks off

But to no avail.
Only rebooting and using "Startup options" and then "Disable driver signature enforcement" worked. But this is one time. How can I do this permanently?

This is extremely ridiculous - I wanted to install USBasp driver (for programming AVR microcontrollers) and I couldn't...

P.S I have "Secure boot" disabled in BIOS.