That's the boot animation.
It runs when the Android subsystem is mostly running but it hasn't started looking for a launcher application yet.
If you had previously enabled ADB you should be able to connect and ask it what it thinks it's doing.
But I guess that you haven't?
With ADB you could just:
Code:
adb reboot recovery
Getting into EDL mode is easy if you have ADB:
Internal test points always work but can be difficult to access and locate.
EDL test cables should work on most recent Onyx.