In a APM2.5+ purchased in December 2012 I installed the latest driver "ArduCopter-2.8.1.zip" in the "APM 2.5" using the Mission Planner desktop utility ("MissionPlanner-1.2.29.msi").
The system does not work. After installing the latest driver and connect to Mission Planer desktop will not let me set it up.
Through the terminal I did a test of all sensors, all are correct, except for the case of the pressure sensor (MS5611-01BA03), which does not show any results,enclose a copy of the screen.
I didn't quite understand what your saying..
Go to firmware, install FW of choice.
Then to set it up you need to connect...
Sorry for my bad English.
I have installed FW Quadcopter OK.
After restarting the APM2.5., ABC LEDs are off.
In the startup process fails the pressure sensor, altitude (MS5611-01BA03).