Hi,
can anyone tell me how can i calibrate IMU. I tried many time but always stuck in first step , and show the unknown error. Also done the degrade & upgrade.

Hi there, sorry to read about your issue, could you please double confirm if you are calibrating the IMU of your Phantom 4 RTK? Please note that it is necessary to calibrate six directions. Do not start the motor during calibration.
Please keep us updated if the issue persists. And a screenshot of the error message will be appreciated. Thank you.

DJI Susan Posted at 3-11 23:41
Hi there, sorry to read about your issue, could you please double confirm if you are calibrating the IMU of your Phantom 4 RTK? Please note that it is necessary to calibrate six directions. Do not start the motor during calibration.
Please keep us updated if the issue persists. And a screenshot of the error message will be appreciated. Thank you.

Hello Susan,
I know there is six calibration direction. But on very first step , I'm waiting to complete the first step calibration. And after 3-4 minutes later got the error message.  
Look at the image's. I followed every step. And the aircraft is alread on the flat level surface.

Ujjawal Animator Posted at 3-12 22:51
Hello Susan,
I know there is six calibration direction. But on very first step , I'm waiting to complete the first step calibration. And after 3-4 minutes later got the error message.  
Look at the image's. I followed every step. And the aircraft is alread on the flat level surface.

Please confirm if the calibration failed message existed after the calibration page goes to the second page or on the first page.
Please also confirm if the firmware is the latest version, if not, please update the firmware. Restart the drone and calibrate the IMU in another location again.
If the issue persists, you can send the drone back to DJI for further diagnosis and service.
Please click https://www.dji.com/us/service/repair to start an online repair case.

Try your IMU cal outside with plenty of light and a view of the sky.

Buenas tardes  que significa error de estabilizador 40021  dji mini 4 pro

djiuser_xKxbYFAH6xRR Posted at 1-25 09:14
Buenas tardes  que significa error de estabilizador 40021  dji mini 4 pro

Hello, there. Thank you for reaching out. May I confirm if the aircraft's gimbal and camera have been replaced or repaired? If not, please calibrate the IMU and Gimbal to see if the problem persists. Note: It's recommended to remove the SD card from your aircraft before performing the calibrations. If the problem persists, we encourage you to send your product for proper inspection and repair via this link. Thank you for your understanding.

djiuser_xKxbYFAH6xRR Posted at 1-25 09:14
Buenas tardes  que significa error de estabilizador 40021  dji mini 4 pro

This is the Phantom 4 RTK Forum. Please do not post questions about other drones here.

The Mini Forum is:
https://forum.dji.com/forum.php? ... peid&typeid=915

Este es el Foro Phantom 4 RTK. No publique preguntas sobre otros drones aquí.

El Mini Foro es:
https://forum.dji.com/forum.php? ... peid&typeid=915

@DJIGamora, isn't it YOUR job to advise users of the correct sub-forum in which to post, and to move mis-postings to where they belong?

When I try to fly RTK drone , it gives a message like ( That aircraft is currently in operation. Try another aircraft ) why it's happening? please Give me solution...

djiuser_wdWHAR2O7gpG Posted at 2-28 10:01
When I try to fly RTK drone , it gives a message like ( That aircraft is currently in operation. Try another aircraft ) why it's happening? please Give me solution...

Do you have a screenshot to provide?
I remember an error like this with GSPro when it tried to connect to the NTRIP server but another device was already connected to it.

Yes ! this is the image