Have several pixhawks for a year, so know them pretty well.
After upgraded firmware to “stable” No response to any motors in motor test, ESC calculation or Armed.
ESC’s work fine connected directly to transmitter channel 3.
Tried loading in plane firmware and then loading in copter several times. Recalibrate and Arm work perfectly.
Recalibrate the ESCs? It could be the minimum throttle is higher for some reason in the new firmware.
I switched to an APM and had this happen, no errors or warnings anywhere…