The symptom
After booting, the Go2 stands with an abnormal posture — leaning, twisted, or falling over — and the problem persists through a restart. (If a single restart fixes it, it was a bad boot position, not calibration. See our power-on guide.)
The official fix
Re-calibrate the joints from the app:
Settings → Data → Machine Dog → imu Information → Calibration
Run the calibration with the robot on a firm, flat, level surface and let it complete — the head LED slow-flashes blue during motor/IMU calibration. A fast red flash means calibration failed; reposition on level ground and try once more.
The warning that matters
The manual is explicit: the Go2 is factory-calibrated, and you should not recalibrate during normal use. Calibration is a repair procedure for a robot that demonstrably stands wrong after restarts — not a tune-up, not maintenance, not something to try “to see if it helps.” If you’re unsure, Unitree’s own advice is to consult support before calibrating. Repeated failed calibrations are a support case, not a retry loop.
If calibration fails repeatedly
A fast-red-flash calibration failure that recurs on a flat surface points at hardware (IMU or a joint encoder) rather than settings. Contact support@unitree.cc or your dealer with the alarm data from the app (Device → Data) — and resist the urge to open the robot, which voids the warranty.