Greetings fellow brethren of the M2P.  I recently took delivery of a used eBay Mavic 2 Pro, and have been going through the usual calibrations of the compass, IMU, and camera gimbal, all of which went smoothly.  When it came to calibrating the optical sensors, however, things didn't go quite as well.

Using DJI Assistant 2, I had the drone connected to the computer via the USB cable and immediately noticed something was wrong because while DJI Assistant 2 recognized the drone as an M2P, the usual list of firmware updates did NOT appear on screen, and there was instead an error message indicating that the firmware list could not be found.   It was only when I connected the drone via DJI Go4 that I found out the latest firmware is installed, and designated with 790 as the last three digits.  I then tried to carry out the sensor calibration procedure, which also failed.

Selecting the optical sensor calibration process in DJI Assistant 2, the checkerboard screen never materialized, and instead, I was presented with a 3-step tutorial on how to calibrate the optical sensors, which was the only function that became active when I tried to calibrate the optical sensors.  Since there was no indication of a calibration of the optical sensors being essential, I skipped that step and decided to take the drone outside for its first test flight, which also did not go well at all.

During my indoor calibration procedures, the controller, drone, and iPhone all linked up seamlessly with a crisp camera image visible on screen, and the camera gimbal responded as expected to my turning the thumb-wheel on the controller to adjust the camera pitch up and down.  When I took the drone outdoors, however, the camera image never materialized, and I was instead confronted with a black screen and a warning of a disconnect between the drone controller and the iPad.  With no camera image and no telemetry, I then decided to take a short flight within visual range, just to see how the drone flies.  There were no anomalies to report during that flight, but there was no camera image to see until I ended the test.

I am writing to this forum in the hopes that M2P owners with more experience than I might be able to figure out why there was no checkerboard screen image visible in DJI Assistant 2 when I attempted to calibrate the visual sensors of the drone, but more urgently than that, I am curious to find out why this drone that produced a nice crisp camera image during my indoor calibration procedures, suddenly blanked out that camera image when I went outside for a flight test.  Any thoughts on what needs to be done here would be greatly appreciated.  Thanks in advance for any insights that can be offered.  For now, the drone is essentially grounded, but I am still optimistic that the fix to these issues will be a simple one.   

I cannot really help with the sensor problems because I have never did this calibration but, if you can get a display inside but not outside then You will have to carry out further checks. You may already have done so but I would try a different mobile device and/or connected cable in the first instance. It is extraordinary that you can have a display indoors but not outdoors with the same equipment.

When I took the drone outdoors, however, the camera image never materialized, and I was instead confronted with a black screen and a warning of a disconnect between the drone controller and the iPad

I agree with yogi that the connection problem sounds like a cable issue. I have experienced that myself, it is advisable to use high quality cables.
How do you connect the cable to the remote? It is reported less problems if you connect it to the bottom USB-A port instead of the micro-USB on the left side of the remote.

I sure appreciate these replies from Yogi053 and ArcticPhoto.   Inexplicably I now have a video feed from the drone and have completed the drone's first flight with no anomalies after I disabled all collision sensors except for the downward-looking ones.  I suspect that the absence of a video feed from this M2P may have been the result of powering up the drone and its controller in the wrong sequence, or possibly too because I had DJI Go4 running in the background after my sensor calibration attempts while trying to fly the drone with Litchi.

Regardless of why that video mysteriously vanished, I am elated to see this drone now perfectly functional and flying smoothly while filming crisp footage.  Since I only ever launch autonomous Litchi missions that stay well clear of all obstructions, I lose nothing by disabling all sensors save for those pointing down that kick in to soften landing touchdowns.   I was worried I might have purchased a defective M2P so it is an enormous relief to see this drone fully operation at last, and despite having most of the collision sensors disabled permanently.

I'm glad you have it flying now, but it should fly with sensors activated. Hey! as long as you are happy that's what counts.

Hi, Muttley7. Thank you for reaching out. Glad to read that the drone is now flying with image transmission. If you're still having an issue with the sensor calibration, please make sure to download the correct DJI Assistant 2 for Mavic 2 Pro which is the  DJI Assistant 2 For Mavic (https://www.dji.com/downloads/products/mavic-2) and follow the troubleshooting steps below:

1. Please check the Sensor Calibration Instructions in DJI Assistant 2. During calibration, keep the aircraft arms unfolded. Notes: Folded aircraft arms may obstruct the vision sensor, which may result in a calibration error.
2. Ensure that the monitor uses a straight-face screen. Curved screens are not supported. If the screen used is not a straight face screen, please change or borrow a straight face screen for operation.
3. Confirm the dimensions of the monitor being used. We recommend using a monitor larger than 14 inches. If the screen is less than 14 inches, the calibration may fail.
4. Please use a soft fabric (such as a cloth for glasses) to wipe the vision sensor lens of the aircraft. Wipe it several times until the lens is clean.
5. Please set the resolution displayed on the computer to the default value recommended by the system.
6. After following the steps above, please reconnect the aircraft and the DJI Assistant 2 for reconnection and calibration.
7. If the issue still persists, please take a screenshot of the DJI sensor calibration failure, and send it to us for further checking.

We hope this helps. Thank you for your support.

Dirty Bird Posted at 2-3 14:54
Try another cable.  Personally I never use the side Micro USB port with Mavic Pro/Mavic 2 style controllers.  I use the bottom USB-A port with a 1' USB-A to Micro USB cable.  The supplied cable for the side connector always seemed flaky to me.  Also this keeps you from constantly having to disconnect the Micro-USB connector to charge the RC.

When Dirty Bird speaks wise drone operators sit up and take notes.  I gotta confess this is the first time I have encountered any mention that the standard USB cable socket can be used instead of the micro USB which always did strike me as being on the flimsy side.

That tiny micro USB connector always did feel as though exerting too much pressure might break something, so this is a revelation to finally learn that there is a much more reliable alternative means of connecting a data cable to the drone.  I am going to try this brilliant idea today and will write back with my findings.     I am very grateful for this innovative hack that simply does not appear anywhere in any documentation.  I just might be able to complete the sensor calibration at long last.

Dirty Bird is the Oracle of Long Range Litchi sorties, and I'm prepared to duke it out with anyone who dares to disagree with this pronouncement haha,

DJI Gamora Posted at 2-3 21:18
Hi, Muttley7. Thank you for reaching out. Glad to read that the drone is now flying with image transmission. If you're still having an issue with the sensor calibration, please make sure to download the correct DJI Assistant 2 for Mavic 2 Pro which is the  DJI Assistant 2 For Mavic (https://www.dji.com/downloads/products/mavic-2) and follow the troubleshooting steps below:

1. Please check the Sensor Calibration Instructions in DJI Assistant 2. During calibration, keep the aircraft arms unfolded. Notes: Folded aircraft arms may obstruct the vision sensor, which may result in a calibration error.

These detailed steps are appreciated, sir.  I will copy and past these instructions and give this procedure another try.  

Muttley7 Posted at 2-3 22:04
These detailed steps are appreciated, sir.  I will copy and past these instructions and give this procedure another try.

Hi, Muttley7. You're welcome. Have a safe flight always!