I updated the Inspire firmware with one battery in it with no problem last night.  I removed the card and deleted all the files, not knowing that I needed to update each additional battery.  Today I re-downloaded the firmware onto the miniSD and re-inserted into the drone, hoping to update the battery.  No luck.  The controller states that a battery upgrade is required, however I cannot the drone to initiate the firmware update.  Any suggestions.

That is a tough one.

Did you formate the miniSD card before you reinstalled the firmware?
Right off the top of my head that is the only thing I can think of.

As long as you leave the bin file does it automatically update each battery when you insert it into the aircraft? And how do you really know that the battery has been updated?

The answer is simple YES. Each battery has to be updated. Do them when
You have already updated your craft with a battery in it. Each battery has
To be updated. It will do it automatically. You take out the card and read the
.txt file on it.