A walkthrough on how to fix Error (149) on the Agras T40 Drone.
Issue: New Agras T40 on RC firmware ending in 839 will not take off due to the error "Unable to take off(149)" and the RC will not allow you to downgrade the firmware to 838.
Cause: New T40 RCs come from the factory on a beta firmware version that makes some drones throw this error code. This beta version is on a new app version as well and will not allow the firmware for the RC to downgrade back to the release firmware version.
Solution: Log out of your account on your RC by going to the icon shaped like a person at the top of the homepage of the app on the controller. Log into the DJI Beta account using the log in information given below. Go to the device screen by selecting the drone icon and update the RC and aircraft to the newest beta firmware version. Log out of the DJI Beta account as done previously and log back into your DJI account.
DJI Beta Account Information:
username: mgbeta03@dji.com
password: mianhua03