Jan 2nd was the first day I powered up my Mavic. Initally, I had my Asus ZenPad S 8 tablet connected to the controller via the bottom USB port but could not use it to install firmware, because for some reason powering the drone on negated the WiFi signal in my house. I turned my laptop on to see what was wrong and watched the available networks box . When I powered on the drone, all of the networks disappeared, including mine and the 'no internet connection' warning popped up on my tablet as well as the laptop. So I plugged my phone, a Kyocera Brigadier into the bottom USB port because it is too thick to fit into the controller and used my phone data to upload the firmware. After about 45 minutes, it reached 99% and became stuck for another hour and a half. I powered everything off and then back on, but the phone would not connect with the controller. So, I gave the tablet another shot and it connected and was somehow able to finish uploading the firmware from 48% without having a WiFi connection. By the time it was finshed, I had had to recharge everything several times and it was 10 hours later. After the upload, I calibrated the controller, gimbal and IMU, tested the motors without the props, went through all of the settings and flew the simulator... all using the tablet plugged into the bottom USB.
Jan 3rd it rained, so I did not fly until Jan 4. I flew using my ZenPad tablet, plugged into the bottom USB, on beginner mode through two batteries, then on Atti and sport mode on the third battery. I tested camera color settings, took stills and video and the tablet worked fine.


Today, Jan 6, I went out to fly and the bottom USB does not work. The controller would not connect with the ZenPad tablet or my phone (Brigadier), although both devices would begin charging. I powered off and on, tried diferent USB cables and nothing worked. I flew the drone with only the controller, in Atti and Sport mode and had no issues.

Again, I really need for the bottom USB to work, as my phone- and it has no case- is just too thick to fit securely into the controller. My Tablet fits into the controller fine and the much larger screen is handy in navigating the touch menu. I am open to any suggestions.

make sure you do not have anything connected in the other port on the controller,  if you do the bottom usb port is in active,,,,  just a thought

For starters, there is no need to calibrate the IMU, it should only be done if you are experiencing flight behavior issues.
And the bottom port only works if the side port is unplugged.
But maybe the biggest thing is those devices are not on the DJI recommended device list.
If you can please try one of those devices and then see if it will work.
Also, when you swipe down the USB needs to say other then "USB for Charging" Try the other options so data will transmit back and forth instead of only charging.


iOS Version v4.0.1.
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Android Version v4.0.1.
Android version 4.4.0 or later. Compatible with Samsung tabs 705c, Samsung S6, Samsung S5, Samsung NOTE4, Samsung NOTE3, Google Nexus 6p, Nexus 9, Google Nexus 7 II, Ascend Mate7, Huawei P8 Max, Huawei Mate 8, LG V20, Nubia Z7 mini, Sony Xperia Z3, MI 3, MI PAD, Smartisan T1.

What about removing both rubber holders from the controller. Some are removing these to fit bigger devices. Also have you tried from phone Settings > Storage > USB computer connection > Try there MTP and PTP.

@DJI-Ken
I'm aware that the priority plug cannot be plugged in while trying to utilize the bottom USB and I removed it prior to even charging the controller for the first time.  Also, I do not believe this is a compatability issue, as I was able to connect with the controller and operate the craft using the Asus ZenPad S 8 tablet (Android 5.0) through the bottom USB port on Jan 2nd to complete the firmware uploaded and calibrate and also on Jan 4th when I flew the craft. The Kyocera Brigadier phone (Android 4.4.2) was also able to connect Jan 4th through the bottom USB and it did connect with the controller today, via the priority plug but not in a manner that is conducive to operating the craft. Because it has to sit off to the side of the controller and the short priority cable is bent back to be plugged in to the phone, since the phone will not fit in the controller arms.

I'm a little unclear as to what you are referring to when you say "swipe down the USB."  If you mean the USB plug in options on the devices themselves, I have them both set on Media mode which is what they were in when the USB was working on Jan 2nd & 4th. If there is a USB option in the DJI Go 4 app, I have looked but cannot find that.  

@Way Wrong

USB computer connection did the trick.

reddboomer Posted at 2017-1-6 14:46
@Way Wrong

USB computer connection did the trick.

Sorry, I meant when you swipe down from the top of the screen of your phone or tablet with the RC powered on and plugged in and changing the USB connection from Charging to MIDI or MTP or other options were available.
Sounds like you did the same thing through the settings menu.
Glad you got it sorted out.