I bought a used Phantom 4, it works as-is but says it needs a firmware upgrade.  Watched the video and installed DJI Assistant 2 for Phantom on my computer.  When I run the Assistant 2 program and plug the drone into the computer the program doesn't recognize the drone.  I've tried plugging in before and after powering up, with and without the controller running/connected and get the same result.  What am I missing?  I am connecting to the computer using the micro usb connection on the drone and usb input on the computer.

Hi charlie98117, may I know what's the current version of the DJI Assistant 2? For Phantom, it is recommended to download the corresponding DJI Assistant 2 from here to double check: https://www.dji.com/phantom-4/in ... ;from=insite_search
You may also change another working cable to verify.

Thanks, I've actually tried both the V2.06 for Mac and V2.07 for PC.  Both were fresh downloads from that site, also tried different cords.  I've also tried connecting to the controller and upgrading via the controller
so thinking it must be a defective plug.  Is there any way to check if that plug is working?  Could I upgrade via the SD card?