hello susan

i have same problem, the gimbal not responding after failed update, just stuck on 99%

I'm using p4RTK drone and recently when I tried to upload the linear mission to the drone then the cam is no longer operational and the drone can't fly. The massage on the RC states the firmware doesn't match between the aircraft and the RC. The current RC firmware verion is 02.02.0505 and the aircraft 02.02.0503 so that must be the reason why the cam is not working or I'm not sure. There is no error massage stating on the RC screen but it's dark, the cam visual is not on. Back on the main page the massage states the firmware not compatible, please update.

I finally fixed my non responsive gimbal wheel on my Phanton 4 by trial and error x 1000.

First calibrate your remote and the Gimbal wheel. You have to turn off the drone first. Move both controller levers in all directions as you watch the display indicator. Next move the Gimbal wheel back and forth.

Power up the drone with the controller still on. Next hold down both
C1 and C2 buttons simultaneously for a few seconds. The Gimbal wheel should now be responsive. Not sure why this works. Occasionally I have to hit both C1 and 2 to reactivate the Gimbal wheel. If you don't use the C buttons during flight just switch their commands to 'not defined'.

In case anyone is still having this problem. I'm getting ready to sell my P4 and when I charged and set up my Phantom I had the limp camera problem. I couldn't get the downgrade firmware to work (I think it's no longer available) but the firmware refresh did work but did nothing.

So after reading everything and being frustrated, I was tapping the camera with my finger lightly and rotating the drone when it started to move on it's own and flap around a bit. I kept doing it and it started working out of the blue. I was getting a message on my phone about gimbal stress? (I'm not sure what it said exactly) but I tapped it a few more times and the message went away and now the camera works.

I did note the following: while I had this problem I could not strafe the aircraft (move right or left). The controller is working fine (the calibration screen did show the right/left stick working). Once the camera started working I could strafe once again.

I get the sense that maybe the compass/gyros can go bad if stored for a long time which prevents the gimbal from activating  (it's been more than a year since taking the drone out for a spin). I'm getting compass error messages when the drone is on my deck (never had a problem before but maybe it's detecting my deck screws?). Once airborne, the messages go away and it works fine. Every landing though the compass message appears when on my deck. Indoors is fine.

DJI Susan Posted at 2017-11-13 00:31
Thanks for clarification. Just as I mentioned before, DJI Assistant 2 is only available to refresh the current 01.04.0602, or update to the beta 01.04.0608. We do not support to downgrade. If the latest beta firmware can not help you, please consider to send it in for fully diagnosis: http://www.dji.com/support

Same for me. Also can’t get assistant on my Mac !

I know this is an old thread, but I was having this issue and not able to resolve until today.

Trying to re-calibrate using the DJI Assist 2 Pro application would fail constantly.

I resolved this by recalibrating through the DJI Phantom 4 App on my iPhone.

Try to connect your drone as if you are going to fly it.  From the app on your phone click the 3 dots in upper Right of screen and go into settings.
Click the Camera Icon and from here try to recalibrate your camera.  (This is what worked for me..... FINALY!)

Hope this helps!