I had experience unacceptable video feed lag under my preivous Spark flight.  I used iPhone 7 plus with recently upgrade to IOS11, DJI Go 4.1.12., and Spark firmware is .600.  Before take off, I did switch off iphone bluetooth.... but the video feed to still lag even with distance 30meters to 100meters.

So disappointed as my previous flight one month ago carry on very smoothly.  Is it because the new IOS11 or Spark firmware?

After check out last night, there is a trick in new IOS11 - if you switch off bluetooth from the control centre which is not really switch off the function instead it just discount bluetooth device connect it.  To REALLY switch off bluetooth still need to go to setting to turn off.  No sure thats the cause of video lag, I might have to try again later.

The Bluetooth bug in the control centre was on IOS11 and has since been corrected as part of IOS 11.1

bfreedman Posted at 2017-10-2 22:21
The Bluetooth bug in the control centre was on IOS11 and has since been corrected as part of IOS 11.1

Which bug do you mean?

Not in my case. I have last update and that “bug” is still on. The only way to solve for me:
-you turn on Flight Mode and toogle wifi back on , the Bluetooth will be off.

JP Santos Posted at 2017-10-3 03:03
Not in my case. I have last update and that “bug” is still on. The only way to solve for me:
-you turn on Flight Mode and toogle wifi back on , the Bluetooth will be off.

There is no bug...
https://support.apple.com/en-us/HT208086

Dirk52 Posted at 2017-10-3 03:15
There is no bug...
https://support.apple.com/en-us/HT208086

The “bug” is not clearly a bug but a strange way of ios not shutting down properly the Bluetooth. In my case, if you use the Bluetooth toogle off button on control center, it doesn’t really turn off the Bluetooth. If you go to the settings - bluetooth you’ll see the Bluetooth button on! So it doesn’t matter if you toogle on or off in control center. Apple did this on purpose, as you can google it. So, my way to disable it when using the spark is toogle on flight mide. Then all bt and wifi are off. Hope this is explain my experience,

ya its a stupid non sense feature iOS 11 has, makes me a little angry..  makes no sense and feels misleading to have that toggle there.  i cannot find a single use case where i would want to only disconnect from all connected BT devices but not turn off BT..  why leave BT on and draining battery and doing nothing for you...what is the point?  other issue i have with BT is it is a privacy risk, i disable BT when i travel because i learned advertisers and hackers love to track people by BT since it is short ranged they can know more or less an exact indoor position depending on beacon placements.  dumb move by apple i hope they change it back to an on off toggle not a pointless disconnect button...  bit like having a wifi toggle that doesnt turn off wifi just disconnects you.. pointless..

as for ios 11 + 4.1.12, for me and my iPad mini 2 the lag has disappeared, still occasional hiccups, that probably related to ios 11's new handling of certain things i'm guessing, but it should get better with updates.  

HereForTheBeer Posted at 2017-10-3 10:56
ya its a stupid non sense feature iOS 11 has, makes me a little angry..  makes no sense and feels misleading to have that toggle there.  i cannot find a single use case where i would want to only disconnect from all connected BT devices but not turn off BT..  why leave BT on and draining battery and doing nothing for you...what is the point?  other issue i have with BT is it is a privacy risk, i disable BT when i travel because i learned advertisers and hackers love to track people by BT since it is short ranged they can know more or less an exact indoor position depending on beacon placements.  dumb move by apple i hope they change it back to an on off toggle not a pointless disconnect button...  bit like having a wifi toggle that doesnt turn off wifi just disconnects you.. pointless..

as for ios 11 + 4.1.12, for me and my iPad mini 2 the lag has disappeared, still occasional hiccups, that probably related to ios 11's new handling of certain things i'm guessing, but it should get better with updates.

You read the link I posted?
For me it is the right and perfect solution.
There are several situations I want to disconnect from a WiFi or Bluetooth device but keep my watch, AirPods, pencil, handoff, AirDrop and so on active. If you use more than only an iPhone it is a very intelligent solution.

Dirk52 Posted at 2017-10-3 11:50
You read the link I posted?
For me it is the right and perfect solution.
There are several situations I want to disconnect from a WiFi or Bluetooth device but keep my watch, AirPods, pencil, handoff, AirDrop and so on active. If you use more than only an iPhone it is a very intelligent solution.

idk, i dont have the spark anymore, but i just think apple's move was stupid still.. i have the mavic so i dont deal with the lag with BT enabled but i still like disabling it when i travel.  

you would think apple would have some other systems for their W1 (and newer) chips other than bluetooth low energy, since everything it uses is synced point blank.. and not 10+ feet away.   

bfreedman Posted at 2017-10-2 22:21
The Bluetooth bug in the control centre was on IOS11 and has since been corrected as part of IOS 11.1

Unfortunately I tried again yesterday even with the bluetooth really turn OFF, but still the video feed start to lag after 50meters away.  So it might not related to the bluetooth function.  I tried with the OTG cable with my iPhone 7 plus, the connection got little bit better and can go to 90-100m then the video feed lag again.  Honestly I feel very disappointed, as the same Spark fly in US was not like it.  The only different new is the firmware and ISO11 of my phone so not sure which one caused the problem.