I found kind of strange workaround to use voice activation.
If I open Deezer play a song for 1-2sec and go back to the homescreen (leave deezer open in background) Voice activation works even if the screen is off.
Strange thing is that deezer...
Flash with TWRP and you will get the Alexa voice assistant from the Mate 9.
This is the release rom of the europe Legend.
When you have got a goldcard, you can use this rom to debrand your phone.
when you want to debrand your phone go to: