How do I find out what operating system I have loaded on my Pixhawk 2.4.8

I originally was running Nutxx but I may have flashed it with ChibiOS and need to figure out what its currently running. How do I do that?

Connect to the Flight Controller in Mission Planner and look at the messages screen.

Messages

Thanks
I didn’t know where to start but can do that much.

The main issue I’m having is my drone will not arm. I don’t think there is really anything wrong with it but its not happy with something. Does anybody here know of a checklist of some kind that can be used to find common arming issues? I had this machine arming find a few days ago.

It will typically tell you right in that same messages screen or in the HUD.The most common head slapper is the Safety Switch…