Don't stay on FCC

[carsco]

Hello.
I've two Spark units, apparently the same.
First one in FCC, all ok. No problem.

Second one do not stay on FCC.
When I close Fake GPS (with phone in airplane mode) and I reload DJI GO, the app ask me if I wanna switch WLAN (correct).
I answer NO (Cancel) but the app reset the setting on CE mode (I see 13 channel on 2.4GHz).

If I connect the other Spark (same phone, same app, all same!) ask me for the switch, I answer Cancel and the Spark remain on FCC.
WHY?
Sparks have same firmware.

What's the problem?

 

[Roland]

If you switch a spark to FCC while using an OTG cable you have exactly the problem you mention.
Do the switch in wifi mode and most likely your problem will be gone.

 

[carsco]

Got your answer too late,
I've solved opening for first time (with this drone) the DJI GO FCC app.
Only one time, then using official DJI GO app now remains on FCC.

I don't know if my methode is right but seems to be working.
Next time (next Spark ) I'll use your methode.

Thanks again.