I have PX4 FMU v2.x with 1.10.1 firmware. I calibrated everything except ESC calibration.
When I click Calibrate at Power>ESC PWM Calibration. It says “Transition denied: SHUTDOWN to INIT”
As I understood it means SHUTDOWN mode is activated, because no battery connected, but ESC calibration ask to dsiconnect battery from FC.
When I start FC with attached battery and usb connected and then disconnect battery it says:
Dangerously low battery! Shutting system down. System does not support shutdown".