I have the latest version of Assistant 2 for my Mavic 2 Pro.

I connected my RC with a micro USB cable and check that my Internet connection is active. Started Assistant 2 and selected my controller. Clicked on Update firmware, and the progress bar confirms that the Update has been 100 % downloaded, and that my RC has been updated. When I re-start the RC and reboot Assistant 2, the firmware has NOT been updated at all.  I did this procedure about 6 times with the sane result. I also tried to upgrade with my CrystalSky hooked up to the RC. Each time I tried to upgrade, GO 4 warned me that the download failed - check your Internet connection. Tried this method a bunch of times as well without success. What a colossal drag.

The final solution, which is NOT listed anywhere on DJI as far as I know, is to hook up my iPhone 6 to the RC and upgrade that way. Hazzah, it worked. The bonus is, the Mavic 2 Pro and its battery are upgraded at the same time.

I'm a newbee for sure, so maybe I'm doing something wrong... but the instructions for new users are lacking from what I can see.

Hi there, I appreciate your time to share your experience of your Mavic 2 Pro. If any case that none of this will work, I suggest you try to uninstall and reinstall the DJI Assistant 2 and retry to update. You may also try to change USB cables. Also, please make sure that Anti-Virus and Firewall are turned off on the PC. Make sure you are connected to a stable Wi-Fi connection for a successful firmware update. For reference, please watch the video tutorial below. Thank you.