Have you tried trimming the throttle down a little?
Tried trimming down the throttle...no dice. Not sure where to go from here. May try to reload the firmware and see what that gets me.
I have seen a fix for this problem before... cant remember where! may have been on the er9x wiki page. It is a common problem tho.
Flashing to ER9x swaps the roll and yaw channels, so the reason you can't arm is because the APM is seeing full right aileron instead of rudder. You probably missed this during calibration because you just run both sticks in circles at the same time, that's how I normally do it.
There are 2 fixes.
1) swap the roll and yaw inputs to the APM; or
2) re-assign the channels in ER9x.
Check out this thread where we discovered the problem.
seems like everyone has the same problems at the same time!
Right, and they beep because they aren't getting ANY PWM signal. not a wrong PWM signal, just flat out no PWM signal.
There are 3 causes for this:
Bad wiring (Likely not the cause if it previously worked)
Bad code (not likely since mission planner connected and you did some calibration).
APM not booting from ESC/BEC power (most likely candidate since the latest code seems to have a bug which requires you to press reset on the APM after plugging in the battery).
Again, this is a KNOWN bug with the latest firmware that it always requires pressing reset on the APM after plugging in the battery. Hopefully it will get fixed in a future release.
So what are the LEDS on the APM doing? This would tell us if the APM booted.