DJI A2 Issue??? HELP!!

[UAV]

I'm facing an issue with my A2 FC on my DJI s900. Whenever I recalibrate the IMU, it blinks a continuous Red LED. Although, when I recalibrate the sticks, on my Futaba 14SG, the Elevator will not go past 0, into the negatives. It always stays centered. The only way to avoid this issue is to start the ship with the elevator trim at half throttle. And it blinks normally. How do I calibrate the elevator trim to go into the negatives??? So it won't stop at 0? Please help.
Thanks

 

[Carapau]

Could you get some pictures of you assistant screens or better yet get some video of the problem?

 

[SleepyC]

The only way to avoid this issue is to start the ship with the elevator trim at half throttle.

What do you mean by this? Your elevator trim is in the center? Or ??