So yesterday I tried to land on a small stool and the bird tipped and started going crazy. I then grabbed one of the legs so it would hit anything else while the motors were still going. Because it went into Atti mode, the only I knew how to shut the aircraft down at that time was to remove the battery. Today I tried to power it up with two fresh batteries, the LED lights were steady red and the Go app says "Battery error, please check" with the overall status stating "System Error". The RC connected to the aircraft fine and I could see through the camera. Tried IMU calibration but didn't help even after normal completion. Tried upgrading to the latest firmware 1.5.something and it took the update but still gave the same battery error message. Thoughts on how to troubleshoot this before I have to send it to DJI? By the way, I tried two fresh batteries with same result. I also inspected all the connectors I could see and they seemed to be seated firmly.