No offense, but neither one of you answered the question IMO.
If I understood this right, and I have the same question, how do you update a spare battery.
I just ordered a fourth battery that will arrive in a few days. My system is up-to-date with all firmware upgrades.
When the battery arrives, do I need to upgrade it and how?
Updating everything at once is obviously not an option. I have also read that you DO NOT leave the bin file on the SD card.
So what is the proper procedure to update just a new battery? Can you just turn only the bird on, insert the new battery and it will update itself? Do you put the bin file with the most recent firmware update and put into the bird and then insert the new battery? Will the bird also try to upgrade again - what are the ramifications?
Hope this makes sense.