Problems with mkblctrl_+, ArduCopter 3.2.1, Pixhawk Hardware

I posted this on DIYDrones, but then thought maybe this is a better forum for my issues.

I have an old Mikrokopter with v1.2 BL-CTRL drivers on it. I connected my Pixhawk i2c bus to it (nothing else on the bus), installed ArduCopter 3.2.1 on the Pixhawk, and powered it all up. Nothing special happened, but I get good data from the Pixhawk and can see it in APM Mission Planner. I have a Spektrum radio connected, and went through all the calibration steps. I can ARM and disarm ArduCopter via APM MissionPlanner, or my radio’s throttle control.

Then I created an empty file APM/mkblctrl_+. Now when I power up the system, the motors immediately begin spinning at a slow (but not very slow!) speed. Note they spin immediately, not only when armed. When I try to arm the system, it tells me to press and hold the button (as before), but now the button never stops flashing, and the system cannot be armed.

I am unable to change the THR_MIN setting (how do I write changes to settings back to the Pixhawk?). I can adjust them, but there’s no change in motor speed. I can’t tell if it’s sending valid commands because I can’t put it into any kind of active mode. The motors just spin and spin.

Any ideas what I might be doing wrong? Is the firmware on my BL-CTRL boards too old or something (it’s v1.2 at least the hardware is)?

Any suggestions would be much appreciated. Thanks!

Were you able to figure out what’s wrong?