Hello,

From the testing I can make a single user level, I believe that with current fw versions (1.00.0207 for RC and 1.00.0400 for AC) , the Spark system (RC + AC + phone) is unusable without OTG for phones that are not dual-band wifi.
My phone is 2.4 GHz only (CAT S60) and this really make all the stuff unusable (in France) : I cannot connect to neither AC or RC after the second power on after reset...

I just tried with a dual band (2.4GHz/5.8GHz) tablet and another dual band phone and thing are better with respect to linking to various components.

I understand that getting a dual band phone would be better... but I believe there should be an option to stick to 2.4 GHz if the user needs-it or the hardware cannot support it. I don't know if this is detectable at software level, but if the AC detects that the pairing device is 2.4 GHz only, it should not try to go 5.8 GHz !

Regards

Thank you for your update.
May we have some feedback about the flight performance after upgrading the RC firmware?

I just had a new flight with updated RC, under those very carefull conditions (did not went far) it seems Ok (but in OTG).

I had issue starting DJI GO4 that I did not met yesterday evening. It first startup and connected correctly, but right after I clicked the GO FLY Ribbon, and got the aircraft status list (All Ok there), the screen went completly black with no way to recover. RC was still responsive, but no feedback at all to the phone. I did not took off under those conditions.
After a few unsucessfull trial, I rebooted phone and got connection with phone feedback and could manage to fly.

As you can see, the experience is still far from perfect and it needs nerves to put it in the air under those crappy starts...

If your mobile device only supports 2.4GHz, after resetting the WiFi, please do not connect it with dual band mobile device, then WiFi channel will be locked in 2.4GHz.
We do suggest you to use another mobile device which is in dji recommended list to test the performance without OTG.
Thank you very much!

DJI Natalia Posted at 2017-7-14 04:05
If your mobile device only supports 2.4GHz, after resetting the WiFi, please do not connect it with dual band mobile device, then WiFi channel will be locked in 2.4GHz.
We do suggest you to use another mobile device which is in dji recommended list to test the performance without OTG.
Thank you very much!

I guess this is not working... At least if I also try using the RC.

Maybe the fact that RC and AC pairs in 5.8 GHz without any choice prevents the AC to lock in 2.4 GHz as it acts as a dual band device ?