Since upgrading the Mavic's firmware is like Russian Roulette, I would like to know what is the best way to achieve success:

1) Upgrade everything at once with Android's DJI Go 4 using the side-USB port on the RC?
2) Upgrade everything at once with Android's DJI Go 4 using the bottom-USB port on the RC?
3) Upgrade everything at once with Windows 10 DJI Assistant 2 using the side-USB port on the RC?
4) Upgrade RC and MP/Battery seperately with Windows 10 DJI Assistant 2 using their side-USB ports?

After bricking my RC using method 2, any advice to provide new failures is appreciated!

I do it like this and no problems still now,
Firts upgrade RC and then the Mavic Pro and battery seperately with Windows 10 DJI Assistant 2 using their side-USB ports.

Almost a year and laways thru the APP and make sure you have strong/fast wifi and or data service.

Thanks for the info

There could be a chance to have the firmware upgraded failure. If the upgrade fails, users can try to restart the update procedure, or use the DJI Assistant 2 to refresh.