Turn on RC2 controller, but not the drone. Select "Profile. Then select (at bottom left) "More," That'll give you a list of your flights. Flights are identified by date and time. Select a flight to display its route map. On the map, there's...
Strange. I have connected my M5P to my PC running DJI Assistant 2 (consumer drone series) and checked for updates. Nothing as comprehensive as the original (and hackable) Assistant 2 which I used with my Mavic but certainly usable for updates!
What has been said here by several people is correct. What's more, most of these people are have years of experience, so deserve some respect.
DJI updates battery firmware occasionally, and when they do, each battery must be put in drone after...