What cause gimbal jerking

Once and for all...Stop eating BEEF JERKY!

Firstly, do a gimbal calibration on a very flat surface with the gimbal clamp removed. Then you will need to learn to fly and pan slower when taking videos. You may need to adjust the gimbal speed and the yaw expo to slow it down a bit. You can also extend the sticks so that your movements are slower. Just takes practice.

Have you tried what Jenee 2 suggested? How is it going? If this issue still be there, post a video about it for better assistance.

I've already do gimbal calibration and try to see either the problem solve or not.

after updating aircraft firmware, the gimbal movement start jerking

you use your own mobile and video what happen to your gimbal jerking and post here so administrator will help u how to do instruction. if they cant see what happen to your gimbal.