Updated to 01.00.0400 this morning. Used DJI GO 4 app, Quad powered up and connected to controller and iPad (Just like I was going to fly). Clicked the red update notice on the GO 4 app start up page and waited. Updated successfully. Turned Quad, controller, and APP all off. Restarted everything and they all linked right up.
Had to reset the EXP settings, and return to home altitude. There may have been other things but I also may have been using defaults in some cases.
Flew two batteries and no noticeable problems.
Good Luck