So, I've been messing with this error for several weeks now and, for me, I know what it IS NOT!
1. It is NOT the SD-Card (although it may have been for some people). Reformatting and replacing the SD-Card with a 16gb SanDisk Extreme U3 has NOT fixed my issue.
2. It is NOT the Main Core Board. I have replaced the Main Core board with two (2) known good Core Boards and the issue still remains. Replacing the core board back into another Mavic pro and they work fine thru multiple re-boots.
3. It IS NOT the Video Cable as, Initially (upon 1st boot) the error disappeared until the next re-boot where it promptly returned, so the video cable is working, as are the cables to and from the gimbal control board and the gimbal control board itself.
4. It IS NOT the cable connections to the Core board, as they are all good and, as previously stated, everything worked on the initial boot after replacing the Core Board.
This leaves me to believe it MUST be a firmware issue. But the drone will not complete a Firmware Refresh or a downgrade with DJI Assistant or DUMLdore V3. In both cases, thru multiple attempts, on various levels of firmware and on 2, Known Good, Core Boards, the update/downgrade fails at 36%. So I can't even update/downgrade the firmware. I'm just about ready to throw this drone into the river!
Also, the drone is at 01.04.0500 firmware.
Any help from the community would be DEEPLY APPRIECATED!!