I have three P3 batteries. When I do a firmware upgrade, do I have to upgrade the Drone all three times to upgrade each of the batteries?
Thanks!

Not sure if you got your answer elsewhere, but this is what you need to do:
1) With battery #1, startup your quadcopter (with the firmware on the MicroSD card) and let the Phantom Automatically start its update
       - This will update the quadcopter and the battery
       - this process could take 15-20 mins or so

2) With your phantom off, put in battery #2 and startup your quadcopter (should still have firmware on MicroSD card)
      - This will update battery #2
      - This process will most likely take less than 5 mins

3) With your phantom off, put in battery #3 and startup your quadcopter (should still have firmware on MicroSD card)
      - This will update battery #3
      - This process will most likely take less than 5 mins


Everything should be updated and ready to go.

NOTE:  On the last battery, once the firmware is done updating, you'll need to turn your Phantom OFF and then back ON to actually fly it right away.

The above post pretty much explains it.
The firmware on the SD card will update each battery you put and power up (as long as whichever update has a battery update.
Also, if you happen to only update one battery and there is a battery update, the app will notify you that a battery needs updating if you install another battery without the firmware on the SD card.

Thanks Guys..