I've recently worked out some distance problems I was having with the Spark.  But twice now, the Go 4 software crashed (for lack of a better term) while I was in mid-flight, and returned to the Android home screen.  Both times, I restarted the software and it readily re-connected to the Spark.  When it did, the Spark was just hovering in place at altitude as if you let go of the controls, and it also appeared to remember where "home" was.  This is a good thing because both times, it was over a quarter-mile away and out of sight.  And, I was able to continue the flight both times.  It was also getting a fair WiFi signal with no "weak" signal warnings.  I've never had a piece of Android software do that.  I am running the current version of Go 4.  I'm using a Motorola Z2 Play with 32G memory and Android 7.1.1.  I'm running the phone in "airplane mode" and trying to run as "clean" as possible by eliminating any other software running in memory.  I should also mention that I'm flying in a VERY rural area, and my nearest neighbor is over a half-mile away.  And, no power lines any where near my flight area.  I can see where this would be a real problem if the Spark suddenly decided to get a mind of its own, or if the pilot lost their oreintation regarding the Sparks position when the software died.

I had very back luck with stability on some phones and better luck on others.  There has been theories that its related to local caching of recorded videos on the phone, or caching with audio.  One thing that I does that seems to help with me, is restart my phone after every two flights. I bought a used nexus 5x that seems to work pretty well.

djiuser_pVzOCZc Posted at 2018-1-13 15:44
I had very back luck with stability on some phones and better luck on others.  There has been theories that its related to local caching of recorded videos on the phone, or caching with audio.  One thing that I does that seems to help with me, is restart my phone after every two flights. I bought a used nexus 5x that seems to work pretty well.

Something is causing the phone to go back to the Android home screen.  It looks like the program is actually terminating, rather than just going to the home screen and running Go 4 in the background.  When I restart Go 4, it doesn't resume where it was, it actually loads up the DJI Go 4 startup screen.

Thanks for your suggestion.

OK - we have some software gremlins here.  I went back into Go 4 program and started to watch the flight record of the last flight when the software appeared to die mid-flight.  While watching the flight record, the Go 4 software stopped again and returned to the Android home screen just like it did during the actual flight.  And, there was no flight record for the return flight after I restarted the Go 4 software and flew home.  But, when I restarted Go 4 and went to the flight record menu, the original flight record that I just viewed was gone, and the only record of that flight was the last part that occurred after I restarted Go 4 after it disconnected from the Spark during the actual flight.  And, this return flight was not visible in the menu the first time.  Something really strange going on here!
What is really alarming about this, is that if it resulted in a fly-away, I would have no record that the flight ever existed!

Same problems with the GO 4 app locking up, finally switched to the Litchi app and the problem was solved.

This also happened to me just about every flight when I used my Android phone.  Luckily, I had an IPhone 6plus not being used and it has been rock solid.

This happened to me too on Nexus 5X. The scariest thing about this is that it takes ages to start the app. Other than stupid games, I have never used any app that takes more than a couple of seconds to load. I would strongly recommend that DJI splits the useless junk out, e.g. video editing - I never even tried that part of the app.

But let's start to help them too, go the /sdcard/DJI/dji.go.v4/LOG/CRASH and find the related logfile.

=====        Device Info        =====
manufactureGE
product:bullhead
model:Nexus 5X
version:OPM1.171019.011
android version:8.1.0
sdk version:27
=====        App Info        =====
versionCode:1027412
versionName:4.1.15
=====        Crash        =====
java.lang.NullPointerException: src == null
        at java.lang.System.arraycopy(System.java:514)
        at dji.pilot.fpv.model.o.a(Unknown Source:32)
        at dji.pilot.flightrecord.DJIRecordService.a(Unknown Source:17)
        at dji.pilot.flightrecord.DJIRecordService.onValueChange(Unknown Source:139)
        at dji.sdksharedlib.c.g$b.run(Unknown Source:12)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6494)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
        Suppressed: java.lang.Throwable: HERE SDK Version: 3.5.0.466
                at com.nokia.maps.MapsEngine$l.uncaughtException(Unknown Source:25)
                at com.amap.api.col.sl3.hu.uncaughtException(SourceFile:170)
                at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:1068)
                at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:1063)
                at java.lang.Thread.dispatchUncaughtException(Thread.java:1955)
=======Thread info======Crash name:java.lang.NullPointerException: src == null
Cause is:null
Thread name is:main 2
Thread count is:285

munchausen Posted at 2018-1-14 23:08
This happened to me too on Nexus 5X. The scariest thing about this is that it takes ages to start the app. Other than stupid games, I have never used any app that takes more than a couple of seconds to load. I would strongly recommend that DJI splits the useless junk out, e.g. video editing - I never even tried that part of the app.

But let's start to help them too, go the /sdcard/DJI/dji.go.v4/LOG/CRASH and find the related logfile.

I don't have a file there called CRASH.  I have one there called NATIVE_CRASH but it isn't for that date.

sorry to hear about your connection issues.  I'm not familar with android based devices, but i must say that i've never had any issues with IOS (iphone) here in Canada.  Hope you find a solution to your connection challenges

Sparky_17 Posted at 2018-1-15 06:18
sorry to hear about your connection issues.  I'm not familar with android based devices, but i must say that i've never had any issues with IOS (iphone) here in Canada.  Hope you find a solution to your connection challenges

I'm slowly working out the bugs, and I think I've found a couple more settings to make on the phone to make sure it doesn't disconnect.  But, the problem seems to be the software itself is terminating.  Maybe my new tweaks will prevent this.  I flew all day yesterday with my new tweaks and there were no problems.

What worries me about those software crashes is there seems to be no record of those flights.

steve_in_TX Posted at 2018-1-15 06:47
I'm slowly working out the bugs, and I think I've found a couple more settings to make on the phone to make sure it doesn't disconnect.  But, the problem seems to be the software itself is terminating.  Maybe my new tweaks will prevent this.  I flew all day yesterday with my new tweaks and there were no problems.

What worries me about those software crashes is there seems to be no record of those flights.

glad you found a solution to your disconnect issues.  fingers crossed it works going forward for you.

No flight records?  now that can be an issue if you run into any issues and DJI needs your data.  Hope you can figure this out too.

Found the Go 4 app also crashed when using the previous version in the flight simulator.  Did not test the last version in the simulator as much, but the program still crashed mid flight.  Found in the simulator if i just hovered or moved around a bit the app was ok, if i raced around, the app would eventually crash.   Maybe the crash has something to do with the flight data overloading.  Once in the simulator the flight seemed to be in ATTI mode, there was no line in the small screen connecting the AC to the home point, and the app did not crash.  Noticed in the flight records people have been posting there is at times a record every fraction of a second, and at other times there are several seconds between records.   Using Nexus 5x and reset dedicated Nexus 6P.   Good luck figuring it out.

My app crash every time I fly

Sparky_17 Posted at 2018-1-15 07:19
glad you found a solution to your disconnect issues.  fingers crossed it works going forward for you.

No flight records?  now that can be an issue if you run into any issues and DJI needs your data.  Hope you can figure this out too.

Well, I spoke too soon.  Flew this morning and incorporated all my tweaks so far.  On the second flight, I was on the return leg and just about to land when the little GPS square on the Go 4 flight screen went blank, and the software unloaded itself and went back to the Android home screen.   The Spark was about 50 feet away from me, and the GPS signal was strong had been showing 14 to 15 satellites and strong WiFi signal.  But, as before, the remote control was still connected to the Spark, and I flew it around a couple more minutes without the Go 4 software  running.    The Spark was completely stable the whole time.  And, as before, I re-started the Go 4 software and it readily connected to the Spark.  And, as before, there is no flight record for that flight, and no CRASH file in the logs.  And, I was taking video the whole time, but there was no video file.

The only thing I can recall is that I had been flying with a video cache size of 8GB.  I think this particular problem started when I reduced the size of the cache to 4GB.  I'll bump the cache size back up to 8GB and try it again tomorrow.

Also thought the newest revision fixed the problem, but was disappointed.
Found the cashe size made no difference.  Try flying around in the simulator and see if the app crashes.  If you hover in place, the app does not crash in the simulator or in real.  Interesting there is no flight data saved after the app crashes.  I'm thinking there is some overflow with the flight data.  Is surprising DJI can't solve this problem.

Shade220 Posted at 2018-1-15 13:52
Also thought the newest revision fixed the problem, but was disappointed.
Found the cashe size made no difference.  Try flying around in the simulator and see if the app crashes.  If you hover in place, the app does not crash in the simulator or in real.  Interesting there is no flight data saved after the app crashes.  I'm thinking there is some overflow with the flight data.  Is surprising DJI can't solve this problem.

After trying cache size along with my other tweaks,  I agree.  Cache size makes no difference.  Also, any pics or videos you take on that flight are lost, (on the SD card or the phone) along with any log files when the software crashes.

The software just dies and goes back to the Android home screen.  So far, when the software dies, the Spark hovers in place, and when you restart the software, it reconnects to the Spark without issues.

I searched for a fix, contacted DJI who suggested I uninstall and install the app in developer mode, nothing worked,  Knowing the app will crash mid flight simply is not enjoyable.  Finally switched to the Litchi app and for $30 the problem is gone.  

I am dealing with the same issue with the DJI GO 4 app shutting down in mid flight. Right now it Looks like my Inspire 2 which is connected to a Crystalsky ultra monitor and a condense controller and all run through the android operating system. I also have the Phantom 4 pro that works through the android system and I have the Mavic Pro with the monitor (Crystalsky 5.5) running through the android operating system.   I don’t have The  ability to run any of these three drones run through the IOS system.  I am waiting for the fix and hoping that this latest operating system update will correct the issue. I love the DJI drones but it seems like we’re all beta testers and shouldn’t that be an issue for the R&D people.
I am not running any third-party programs that might or would interfere with the android operating system program.

My experience on  using MAVIC 2 PRO with the latest firmware update(Nov22,2018),Samsung S9 Note latest updates on Dec 12 2018, DJI GO 4 Latest update ,SD card SCAN EXTREME 128 GB , Cache files is about 2GB size audio recorded during flights,
Almost every take off once time DJI GO 4 crushed back to Android home screen, I can still restart the app and continued the flight and RTH is still as recorded ,which good point. Can anyone give a solution how I can eliminate this scary  issue.

its obviously DJI GO 4 is not fully compatable with Android sytem while Litchi developers could managed to make their apps smoothly run on any Android devices. But DJI clearly states using any third part apps i.e. LITCHI ,coud void the warranties.
Dear DJI
None of us intending to use any third party apps unless you could manage to give use a fully compatable app.if I use Litchi never experinced mid flight shut down. So please ask your engineers do something .

This happened a couple times on my Android "Motorola Turbo," but never on the iPhone 6+.

Spark seemed to be responding to the remote fine, so I just flew it back.

steve_in_TX Posted at 1-13 17:09
Something is causing the phone to go back to the Android home screen.  It looks like the program is actually terminating, rather than just going to the home screen and running Go 4 in the background.  When I restart Go 4, it doesn't resume where it was, it actually loads up the DJI Go 4 startup screen.

Thanks for your suggestion.

Switch off power saving mode for GO4 app. This may help.