I  just experienced the broad extended problem....dreaded battery brick because failed fw upgrade.

I purchased in january an  fly more combo. This was the 3-rd battery used only some 5-6-7 flights. I was in vacation in mountains when toked that battery as last one charged for another flight..placed in the mavic and the app say about firmware mismatch etc....choose update ...the battery fw started to write but stopped at 97% ...the battery locked with middle two led lighted...only options to shut down the mavic was to take out the battery. After that any attempt to update again failed because nor the app nor the assistant when returning home from  vacation was not requested to update again.




Now the battery is completely dead depleated from current ...nothing to do because the 6 month warranty expired....just losted 100$ because the app requested an battery update.




If U will encounter this problem and the assistant still detect a problem and request another update but your battery already under 50% connect your remote to pc with mavic started and update that way...this will bypass that stupid 50% battery request...

Sorry to hear about your case. In fact, if the battery is lower than 50% power, users try to keep it in charge for about 2 hours, and then mount the battery to the aircraft, connect your drone to the computer and try to upgrade it via DJI Assistant 2 again. Note that the LEDs of the battery will not flash because the middle 2 will keep lighting until the upgrade is successful.

DJI Thor Posted at 2017-8-29 23:01
Sorry to hear about your case. In fact, if the battery is lower than 50% power, users try to keep it in charge for about 2 hours, and then mount the battery to the aircraft, connect your drone to the computer and try to upgrade it via DJI Assistant 2 again. Note that the LEDs of the battery will not flash because the middle 2 will keep lighting until the upgrade is successful.

Tx for the reply.
The problem will be that the bricked battery even if it still charging directly thru cable, not thru smart hub...the mavic will not read it and will not know the voltage even the battery is full will refuse to update.
For that the solution it is to connect RC and update thru that.
But for me the problem was that the assistant and apk will not start the update procedure again...tried 100 times in vain...and when tried to update completely the mavic with the battery in it the process stopped every time when reaching battery upgrade part  ...failing because unable to update battery. Now the battery is completely dead...refusing even to charge directly thru port...a lost cause...

I searched thru net but not able to find an electronic logic board as a replacement for my bricked battery...any place to find that part?

It's a shame DJI pushes these few updates on people and won't at least warranty that part for the life of the product.  Seems DJI is the reason your battery failed.

Yes it was an dji induced fault from what I lost money ...at least they don't force yet updates to the battery...still you could choose to ignore the update and the mavic will still fly...they offer only 6 months warranty to batteries...indeed they should offer more at least as they perform that firmware upgrades generating problems from a lot of users, maybe with amended recharging times...like they already have imposed...now it is at 200 charges I think...

daivatam Posted at 2017-8-30 05:00
Tx for the reply.
The problem will be that the bricked battery even if it still charging directly thru cable, not thru smart hub...the mavic will not read it and will not know the voltage even the battery is full will refuse to update.
For that the solution it is to connect RC and update thru that.

I am so sorry to hear about this case. Would the LEDs still light up on the drone? If the power is drained, the battery might not be recovered by over discharging. Sad story.

DJI Thor Posted at 2017-8-31 23:33
I am so sorry to hear about this case. Would the LEDs still light up on the drone? If the power is drained, the battery might not be recovered by over discharging. Said story.

Tx!

The board now is dead completely...after the last attempt to update fw the 2 led remained in a state in which they pulsed more rapidly than the previous sequence and over night they go in off state...I crack open the battery and I charged it with my professional balance charger...the cells are ok but the logic board is dead....no response from it anymore no led lit...verry annoying fact that just I lose that like new battery that sudden because a 5-minute fw upgrade request at least if it was cheaper than 100$
dji should introduce an extended warranty for failed fw updates....the data could be easily obtained from bird logs and false cases could not be possible...