Thanks for taking the time to find this solution.
Now I ask you, how many times in a row have you succeeded in doing this successfully?
Some years ago someone suggested an idea like this to me, do precise steps. I don’t remember them right now, but I had them written down. It seemed to work initially, only that after a very few times, maybe 4 or 5, something got jammed and while repeating the same procedure starting from all the hardware switched off, and the tablet always dedicated only for that use, in airplane mode, well, that ■■■■■■■ Galaxy S2 T819, it didn’t want to work and couldn’t be used with DJI GO 4.
After that other attempts made in the following days, sometimes it connected and many other times not, until I decided to leave it forever.
Precarious behavior like that, with or without the developer mode activated and playing also with various combinations of settings, is unacceptable and unbearable, so much time consumed just to do nothing and loose the possibility to fly, is too silly.
There are many other tablets available on Earth that can work almost always without problems.
And the old T815 and T820 are usually ok, but I prefer to use others with USB3 type C offering less connection instabilty, like a Samsung Galaxy Tab S5e (SM-T720) and a Xiaomi Mi Pad 4.
So far this method works every time. However, you have to remember to do everything in the right order. When you turn off the drone, unplug and turn off the tablet and start all over again …
Developer settings can be turned off because changing any of them will do nothing. You have to spend a little more time when you want to start flying but apart from Dji Go the rest of the apps I tested worked very well.
Well… good for you.
I did as per your instructions here, however with DJI GO4, not Litchi. I have not used it since 2016, but I could possibly install it.
As soon as you insert the USB connector into the tablet (off), the battery charging procedure begins (even if the battery is at 100%) and you are forced to wait about 20 seconds to be able to turn on the tablet, that is until it finishes to analyze its battery and shows the actual % level.
At that point you can turn on the tablet with a long press of the switch, but finished the start, DJI GO4 does not start automatically (and this fact already indicates that it does not work). Starting it manually and it shows you the generic window for all the possible drones you could connect (with Mavic 2 already selected), but if you select the aircraft you currently have already connected with the RC, it’s useless.
It is as if you have to do the pairing between aircraft and RC, DJI GO4 does not see it! Repeated the whole procedure some times, with two Samsung tablets, the ones known to be problematic, if not impossible to use: one 8" T719 and one 9.8" T819 and with one Inspire 2 and one Phantom 4 Pro.
Now can this be enough, or I need to try also Litchi?
For anyone with problems getting the S2 to connect, I managed to get a T819 to connect by changing the tablet over to the Lineage OS ver 17. It will take some googling and effort with many hours of playing with the ODIN flashing tool, but it works perfectly in the end. I don’t need all the Samsung bloatware as the tablets are dedicated to their respective P4Pros.
I have been using the T-813 for 2 years without any problems flying my Mavic 2 Pro using Go 4 app but it will not connect with a newly purchased Phantom 4 Pro v2.0 under any circumstances. Also use DroneDeploy and switch back and forth between DJI Go 4 and DroneDeploy and have no problems with the Mavic 2 Pro.
Well, good to know, the behavior of those Samsung Galaxy Tab S2 series is really crazy and close to unpredictable, especially using the DJI GO 4 apps. However to a report like this, should be added also at least the Android and DJI GO 4 versions installed on the tablet, these could be important data to know.
Just received this from DJI support. First shocked my the quick response to and email from this morning but not surprised that non of the suggested solutions worked. Waiting for response to their request for info on my P4PV2.0 and Tab S2!!
（DJI Support）
2021年12月14日 GMT+84:42
Dear Rodney Harvey,
Thank you for contacting DJI Technical Support.
We appreciate the time you provided to us and we are sorry for the problem you are having but no worries, we are here to assist and help you out.
If DJI GO 4 App prompts “Disconnected” (as shown in the figure below), please follow the steps below to troubleshooting.
To use the interface under the remote control, unplug the left side wiring;
Re-plug the data cable (try both the mobile phone and the remote control, please pay attention to plug it back 10 seconds after unplugging it);
Restart the remote control;
When using an Android device, please remind the user to turn on USB debugging on the phone (DJI GO and DJI GO 4 can be turned on in App>Settings, and must be turned on in the mobile phone system when paired with DJI Fly);
Note 1: Most devices need to be connected to charging only, and some devices need to be set to media library (MTP) or camera (PTP) mode.
Note 2: For Huawei equipment, it is recommended not to use original Huawei cables.
After making sure that the important information has been successfully synchronized, try to reinstall the APP(Please back up important information before removing the App), restart the mobile device, and then reconnect;
Try to switch devices with different operating systems (Android ↔ iOS);
Please follow the above steps to try, if the problem still exists, please provide the following information:
Mobile device information, including mobile device model and system version;
Related operation videos (it is recommended to shoot the operation process from a third-party perspective);