I have spark fly more combo for 5 days now . I have to say that this is an awsome drone...I have never had any problems with gps loss any abnormal behavior or anything else .I have never callibrate anything because never promt me the app.My fligh distance is 3 km tottal untill now...I use connection as advised with htc 10 to remote never lost connection or anything else or app crash, i only get signall image transmition in 120 meter altitube and 200 meteres distance never used an otg it connects always in 5.8 ghz. But distance for me i beleive is ok...I have to say that i want fb live in my android phone htc 10 , i want better distance and some zoom in the camera.....I also want better auto camera setting and more options in manual modes ....

Thanks for the feedback. Flight distance sometimes relates to the flight environment, we would suggest that you fly the drone in an open wide area. Also, the position of the antennas makes a great effort, too. Check the position of the antennas for the remote controller. Distance should be greater than height during flight. Instruct customers to make sure the remote controller’s antennas are positioned parallel to and are pointed towards the aircraft.  But Spark doesn't support zooming in the camera, this due to its hardware.
We have the FB live tutorial for your reference, but Android phone doesn't support using the internet while WiFi connection, we can only suggest using an Apple device:

Hello, did you push your sparks to limits using RC?

I did not push it to the limits due to lack of experience....

Thor, everything I have read and DJI's own video say the antennas should be perpendicular to the line from RC to drone.  

    Here is the tutorial on RC and antennas