# Restricts all controllers to the specified transport. Default value
# is “dual”, i.e. both BR/EDR and LE enabled (when supported by the HW).
# Possible values: “dual”, “bredr”, “le”
ControllerMode = bredr
Restart bluethooth service afterwards: sudo /etc/init.d/bluetooth restart
After the pairing you may put the config back to “dual”. Only pairing seems to be affected.
2 Headphones to pair mode
Slide button 2s or use their app (assuming already paired with your phone).
3 Settings -> Bluetooth -> +
Click on PIN options and select Fixed PIN Do not pair.