My "old" apm copter just got a new heart today, the new px4 firmware on my auav-x2. 
I couldn't calibrate my esc's. Why?
I disabled the safety switch CBRK_IO_SAFETY, the powermodule CBRK_SUPPLY_CHK and the usb CBRK_USB_CHK but I still get a battery timeout when I want to calibrate the esc's.
I use the lstest qgc and px4 firmware master.