I have the Mavi Pro.  Used it several times.  Today finally figured I would upgrade from 1.03.0800 to 1.03.0900.  I used my smart phone connected to my remote to do the upgrade.  The Drone was connected to the remote also.  I got the firmware downloaded and started the upgrade.  It failed because the  the drone shut off on its own.

I then figured I would connect the drone to my computer and do the firmware upgrade via the DJI Asisstant.  The drone upgraded just fine.  I then connected the remote to my PC.  I started the upgrade.  As soon as the program got done with the download (was downloaded already from doing the drone) I get failed error.  I tried several things like restarting my PC, the remote and kept getting the same thing.  So I tried to connect the drone to the remote and fly.  I kept getting the error on my phone Cannot Take off and Error code 0200 came up.  I tried several things like turning off and on, different order of turning on and still the same thing.

So I figured it was the firmware.  I downgrade the drone to 1.03.0800.  I tried connecting the remote to the drone and kept getting Cannot Take off error.  I could not start the motors or anything.

I again tried to upgrade the remote and still get the failed error.

I have upgraded my firmware several times up to this point with no issues (ususally have to use the DJI Asisstant because the drone always turned off before the upgrade was complete).

Going to Hawaii in two days and have a dead drone on my hands.

Any help would be greatly apprecaited.

What phone/tablet/OS are you using?  Try re-setting to factory and then do the update thru your phone. Make sure you have a fast WIFI.

Sorry to hear about the issue you're faced with. Have you tried to re-install the DJI assistant 2, then upgrade the RC again? Please try that , if it is still the same , please provide some screenshoots of the error messages(both in the APP and the DJI assistant 2).
Please follow the steps below to connect the RC:
1. Connect the RC to your PC when the RC is powered off.
2. Open the DJI Assistant 2, then power on the RC.
3, Then, upgrade the firmware.

I install DJI Assistant 2 on a ew computer.  Connected the remote to the computer and when the program found the remote I did the upgrade.

From DJI Assistant 2 when I plug in the remote I see the attached.  Also attached is the error I get in DJI Assistant.  
I am still not able to upgrade the firmware.  I did export the logs from the remote but it was 35Meg in size zipped up so I was not able to attach to this post.

Also, I am using a Samsung S6 running Android 7.  Never had any issues until yesterday.

Thanks!

Sorry only one picture got attached.  Here is the error screen I see on the Assistant.