We've got two new APM 2.5s from diydrones, and are just getting started with Arducopter (but aren't new to Arduino or embedded systems).
After downloading 2.8.1 hexacopter to them with Mission Planner, we were able to communicate with them through CLI, and connect to them with MP, but not do much else (like radio calibration). Apparently because the APMs kept resetting themselves every 5 seconds (according to message on the console).
Upgraded both to 2.9, and now one appears to be working okay when hooked up via USB. But the other one can only communicate via CLI: trying to connect via MP times out every time.
Is there a debug tool to help isolate what's failing (like, say, a diagnostic sketch for the APM, or an app that would show me what's going on over the Mavlink link? The Windoze version of MP unhelpfully closes the command prompt window on startup, so I can't see its debugging output like on Linux)?