For me, it was always a little disturbing when calibrating with the nose down because the gimbal would go nuts no matter which tilt angle I put the camera at before the calibration.
With it on the side, the gimbal behaves much better.
I called DJI Support about this, they said that it doesn't really matter if the nose is down or to the side but the main reason for performing the calibration with the camera sideways was to keep the gimbal stable during the vertical part of the calibration.
Like others, I wish DJI would have at least mentioned that in their release notes.
If you think about it, all of DJI's diagrams show the I1 with the nose down. They had to purposely make a new drawing to show the I1 in the vertical position with the camera facing sideways. This makes me believe that it was not a mistake. DJI Support pointed that one out while on the phone with them.
They also pointed out that it didn't matter which way it was pointed to start the calibration. As long as you continue to rotate it till the status light changes, it's fine. I've noticed in some cases that I would have made a turn more than 360° when the status light changed. I wasn't moving very fast (it makes me dizzy to rotate in a circle too fast. Lol).
Each time I try calibrating it with the camera pointed to the side, it passes the calibration unless I'm too close to something metal like my van
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I just got back from a cross country trip so calibrating at each location (300 or more miles apart) seemed to be a good idea even if the app and status light indicated it was normal. Using the method depicted in the app worked everytime and it always flew with good GPS accuracy. I just wish the wind had been less than 18 to 20 mph at almost every location.
A bit off topic here but before every flight the IMU would indicate normal on the first page in the app. I always hit the Check IMU button in the MODs page even if the first page indicates normal, most of time it indicates that it's not needed but sometimes it does need calibration, three out of 21 flights the IMU needed to be calibrated. Maybe it was because of the temperature changes? In every case, I let the I1 electronics warm up before checking it.
Just my 2 cents worth.
Joe