I am trying to make my usb device(hci0) pairable to another device, despite having set the simple-agent capability to NoInputNoOutput the device always asks me for a password i do this command:
bluetoothctl --agent=NoInputNoOutput
Agent registered
[bluetooth]# default-agent
Default agent request successful

I would like to be able to make hci0 connectable as headphones or without any password entry by the user, does anyone have any idea how to do it?