Yes stoped the service before starting the ArduCopter.elf again.
I tried what you suggested with a newly flashed image on a RPi 2.
I did sudo apt-get update and sudo apt-get install apm-copter-erlebrain
Still the same error.
erle@erle-brain-2 ~ $ sudo ./ArduCopter.elf
Raspberry Pi 2/3 with BCM2709!
Init APM:Copter V3.4-rc2 (f46a31d0)
Free RAM: 262144
FW Ver: 120
load_all took 771us
0 0 0 DataFlash_File: buffer size=16384
� Q}�AK8963: Wrong id
AK8963: Onboard compass not detected
HMC5843: Could not detect version
HMC5843: External compass not detected
No Compass backends available
COMPASS INIT ERROR
� Q��Init Gyro
It looks to me that there is an issue with the PXFMini since both, the RPi Zero W and the RPi 2, have the same problem.