The story in short:
I'm trying to get some data from Android(or WP10) phone to Hololens using RFCOMM Serial profile(rfcomm is important point, so unfortunately can't use BLE features or Wifi). Haven't succeed a lot with doing as Hololens=BluetoothClient(same code for WP10 works like a charm), so change direction to Hololens=BluetoothHost. And it actually works, but with next issue: the attempt to connect from client device silently fails in connection event handler.
In same case with same code in UWP app on hololens the system consent dialog to allow using device from app appears. So user confirms it and everything is ok. In Unity app - nothing for user. So my only way for now is close app, go to Settings -> Privacy -> Other devices and manually allow device/app usage.
Is there any way to show such a dialog or some alternative inside Unity app? I'll appreciate any help.
Some code sample and details are in my SO question