I have a DJI Phantom 4 RTK and during a firmware update the controller went to a black screen and no longer responds.  The fan is running, the red light is on the faceplate, and it will not connect to DJI Assist with a cable.  Every so often an alarm will sound, about once per second.  If I wiggle the joysticks, it stops.  My guess is that the firmware I downloaded to install was somehow corrupted, but I really don't know.  Any ideas?

Hi! You might be better off posting your question in the 'products' section of this forum.  That is way more active.    -   https://forum.dji.com/forum-129-1.html