As I saw already a few threads around this topic but no clear view from my site.
(Also the you tube movie was nice but not ansering all questions.)

My questions:
- Is it possible to use 3th party app's (like Lichie / FPV Camera).
- If so, can I start on both controllers/device different app's. For example: On the slave FPV Camera and DJI go 4 on the master.
- What about triggering RTH. Is this when both controllers are out of reach?

Is there anybody from DJI who can answer those questions? Thanks!

As far as i am concerned. for Mavic second mode,  the 3rd party app is not confirmed to be supported.  i am afraid not.
RTH, Mavic goes into return to home progress while the master RC lost signal and as well as the slave RC lost the signal at the same time.  
You can also trigger  RTH  by hand on the RC at the time it works.
May help~

Is it possible to use 3th party app's (like Lichie / FPV Camera).

Yes, and many of us do use Litchi and / or other third-party apps. However, if a crash occurs while using something other than the Go app it may be harder for DJI to diagnose the cause, which means that they might refuse to provide a free warranty repair if you crashed while flying with (for example) Litchi. And Care Refresh specifically excludes repairs for damage caused by third-party hardware or software.

If so, can I start on both controllers/device different app's. For example: On the slave FPV Camera and DJI go 4 on the master.

I haven't tried it myself, but I'm pretty certain you probably can.

What about triggering RTH. Is this when both controllers are out of reach?

Based on the comments I've read, I believe that the aircraft would have to lose the connection to both remotes for RTH to be triggered.

Thanks DroneFlying

SHamers, I'm not 100% sure about your idea --- if you think about it , it will not work --- I believe
               the second controller will be detected as if it was another RC Drone or Plane system and not
               connect at all ---- even though they can control the same system, the GO4 app and Litchi are
               not compatible at all and with the litchi program
               it has a more complex remote control Key Mapping amongst other operations.
               This is just my opinion.
FlySafe-FlyFree

SkunkWerxs Posted at 2017-4-26 04:42
SHamers, I'm not 100% sure about your idea --- if you think about it , it will not work --- I believe
               the second controller will be detected as if it was another RC Drone or Plane system and not
               connect at all ---- even though they can control the same system, the GO4 app and Litchi are

I believe the OP is talking about the dual remote support where there's a master / primary and slave / secondary controller and is wondering if, for example, Go could be used on one and Litchi on the other. The remotes never interact with one another but only with the aircraft, and it doesn't know what app is being used with either remote. In fact, you could theoretically use the remotes with no mobile device or app at all. The app is just a user interface for the remote, so I can't think of a reason why you couldn't use two different apps with dual remote support.

DroneFlying Posted at 2017-4-26 04:49
I believe the OP is talking about the dual remote support where there's a master / primary and slave / secondary controller and is wondering if, for example, Go could be used on one and Litchi on the other. The remotes never interact with one another but only with the aircraft, and it doesn't know what app is being used with either remote. In fact, you could theoretically use the remotes with no mobile device or app at all. The app is just a user interface for the remote, so I can't think of a reason why you couldn't use two different apps with dual remote support.

DroneFlying, The reason I believe it probably will not work is because in order to setup a master primary and
                   slave secondary controller is due to the fact you need the GO4 app to do so and would
                   automatically reset when the master , slave controller settings when the controller is powered
                   off ---- if the above were not true anybody with a Mavic controller can take over your Mavic ?
                   In the owner manual it states you can fly up to 3 DJI Drones at the same time without
                   RC signals interfering with the others -- This is why I said it would see it as another system
                   It is a good question   
                  

SkunkWerxs, I think you make the controller master or slave just the first time togher with the Mavic. (By pushing on the small button). So you can't take over an other drone.
I think the slave/master parameter is stored on the controller/drone.

I think ;-)?

SkunkWerxs Posted at 2017-4-26 05:07
DroneFlying, The reason I believe it probably will not work is because in order to setup a master primary and
                   slave secondary controller is due to the fact you need the GO4 app to do so and would
                   automatically reset when the master , slave controller settings when the controller is powered

Yes, the initial linking would probably have to be done through the Go app as described in the manual, but the link to the remotes remains after that. So you could then shut down Go, start Litchi, and fly the aircraft just as always.

SHamers Posted at 2017-4-26 05:15
SkunkWerxs, I think you make the controller master or slave just the first time togher with the Mavic. (By pushing on the small button). So you can't take over an other drone.
I think the slave/master parameter is stored on the controller/drone.

I think the slave/master parameter is stored on the controller/drone.

I believe that's correct: the aircraft knows which remote -- or which two remotes -- it's associated with and can be controlled by, but it doesn't know or care which app is used to interface with a remote.

Sounds Logical :-)

The only issue what could happen is that when you use Litchi and start a waypoint/mission and use the Go app on the slave controller that the mission terminated by using the GO-app/controller.

DroneFlying Posted at 2017-4-26 05:22
Yes, the initial linking would probably have to be done through the Go app as described in the manual, but the link to the remotes remains after that. So you could then shut down Go, start Litchi, and fly the aircraft just as always.

DroneFlying , This is a very interesting thread --- I think I'm going to try it ,I do have two remote and two Shield K1 tablets with the latest GO4 and Litchi app --- I'm gonna try this
                    after trying to take off with Compass error to see what would happen as I said in the other op's post .
                    Also Want you to know I do have parts, Mavic Shell and arms with motors just incase.
I'm still working on extra Mavic electronic guts lolllll
FlySafe-FlyFree

SkunkWerxs Posted at 2017-4-26 06:34
DroneFlying , This is a very interesting thread --- I think I'm going to try it ,I do have two remote and two Shield K1 tablets with the latest GO4 and Litchi app --- I'm gonna try this
                    after trying to take off with Compass error to see what would happen as I said in the other op's post .
                    Also Want you to know I do have parts, Mavic Shell and arms with motors just incase.

Good luck and let us know how it turns out; video would probably be interesting. Just make sure it's in an open area and that you get some altitude soon after takeoff. Otherwise even with spare parts things could turn out badly.

Good luck and please let us know! Thanks

DroneFlying Posted at 2017-4-26 06:49
Good luck and let us know how it turns out; video would probably be interesting. Just make sure it's in an open area and that you get some altitude soon after takeoff. Otherwise even with spare parts things could turn out badly.

DroneFlying , I'm on it right now --- Will try to setup video also

SkunkWerxs Posted at 2017-4-27 08:41
DroneFlying , I'm on it right now --- Will try to setup video also

Well? Any luck?

DroneFlying Posted at 2017-4-27 14:27
Well? Any luck?

I posted a video check it out you will be surprised --- I did the Compass error test first -- tomorrow I'll get a friend to man the cam cuz I stink at it  

{:4_181:}

Where did you post the video?

Sorry I found it! I wait for the second controller test :-)))

Hi Skunkwerxs, could you already do the test with 2 controllers with different app's?