Altitude problem and Bad AHRS

Hi,
I’ve installed Arduplane 3.7.1 into a Pixhawk. Everything seems working fine except the altitude. The altitude fluctuates all time. My plane is stable on my desk and altimeter is not stable. It changes between -1m and 1m. Sometimes it jumps 30cm. If I lift my plane 2m (for example) the altitude marks 2m and then with the plane at 2m, the altitude goes to -0,20 or other incorrect altitude. If I open the tuning window, barometer seems working fine. Just for testing propuse I installed the Copter firmware and altitude works perfect (very stable). The problem is with Plane firmware.
Other issue I see, with the Plane firmware GND_TEMP is always in 25 Celsius, and with Copter firmware, GND_TEMP is according to the environment temperature. Is that fine?
Other issue that maybe it’s related with the Altitude is a message with “Bad AHRS” when I turn on my Pixhwak.
Any idea how to solve the altitude fluctuating problem?
Thanks,
Marcos

Solved:
“Copter grabs the home location (including alt=0) at first GPS lock and then once more when armed. Plane does it differently. While unarmed, it constantly resets home. So, if you arm the plane you should see the same behavior as copter.”

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