I jsut tried to upgrade a new battery to 1.6.  It seemed to go very quickly.  I got one of the D-DDD's and a green light on the gimble and it was all over in less than a minute.  No other sounds.  I checked the SD card, but there was no status txt file.  How do I know the battery was upgraded?

My DJI Go alerted me that my battery needed to be upgraded. Try connecting to the bird and check the battery status on the app.

cassius Posted at 2016-1-6 08:16
My DJI Go alerted me that my battery needed to be upgraded. Try connecting to the bird and check the ...

When I went to check the txt file on the SD card with my computer, there wasn't any so I concluded that the update failed.  The app also told me that the battery still needed updated.
I finally had to reformat the SD card with my computer (I had done this before with the aircraft thinking that would be ok, guess not) and tried to reinstall the firmware.  This time the aircraft did all the usual stuff during updates and it was successful.  The process of updating firmware seems really finicky.  I'll remember this for next time.