I just loaded a 100% battery in to upgrade to Firmware .800.  I am on a slow connectionand it took more than 1.5hrs, so the battery ran down to <50% during update.  It had gotten to 100% on the download.  So I shut the aircraft down (I was connected directly via USB port, using Assistant 2 software) and loaded a 100% charged battery.  I continued the upgrade and it went through the updating part and got to 100%, then it started the transmitting part and got to 44% and then all the lights went red on the drone.  The battery started flashing the MIDDLE two lights green and the third light from the top a double blip every so often.  I waited a long while, and finally got this error..

Error log

No amount of button pushing on the battery would turn it off, so I took it out of the drone.


I then (reluctantly) loaded a new battery (100%) and tried again.  It went right through the process and at the end said it had upgraded to .700 - !!!! That's what I was on already.  

So I tried again for .800.  It stopped at 44% again on the "transmitting" part of the upgrade, when all the lights went RED again.  And now I have two batteries stuck in limbo with the middle two lights flashing every so often.

Battery

The lights on the batteries are still flashing every so often - I have tried holding the button down for 30 seconds or more, they do go off but as soon as I release the button, they come back on and remain in the same state.

I put them in the 4 bank charger - don't know what will happen.

Is there any way to reset a battery?

And why did this happen during upgrade to .800?

Can you power up the RC and Mavic?

If yes, power up and connect both and press Rec button

plug in USB and open DJI Assistant 2 and update again

I had this issue as well. The only way to solve this issue was to hook up the mavic to the PC and run the latest Assistant Software 2.. and update it that way.
The batteries will stay in that mode until they're fully done with the update.

I used the app to upgrade using my third and last battery.  Then I went back to the assistant 2 and used it to update the two "bad" batteries.  Problem solved.  But why is it so tricky?  Not really happy so far with DJI app and Assistant2 software - seems overly "clunky".  There should be a way to separately download the update and apply it when you need to, rather than have to be connected to the internet for such a long time (on a slow connection).

I am hoping that when I fly later today that the app doesn't crash as it always has with .700 every time I press the "REC" button on the RC or the phone.

I've had so many issues, not only with the batteries but the raw photos shot on portrait mode. I had many fights with dji support and they kept telling me to return the craft. I kept telling them it's a software issue. I ended up downgrading and all my problems went away.

Yep,

I'm getting closer to that stage to Alex.  The thing crashed every time I hit REC again yesterday after all the latest updates.

Hi, had similar issue, try to read here: http://forum.dji.com/forum.php?m ... &fromuid=502089