I have just substituted my Pixhawk by a Pixracer and I'm puzzled by what seems to be a difference in the arming sequence. ( It could be that also PX4 code has changed in the last 3 months since I updated? )
Previously to Arm the Pixhawk you had to press the safety button and then arm with the radio ( lever bottom right corner).
To Disarm you could either press the safety button again or you could do it with the radio ( lever bottom left corner)
However now with the Pixracer it seems that pressing the button is no longer necessary, it can be arm directly with the radio.
But I have not found any way to disarm with the radio... which seems odd
Any ideas of what is going on and why the difference in behaviour??
As always links to docs that explain this also welcome.