I read that Aspirin 2.1 doesn't need a calibration file
nope, wrong...
There are only default values for gyro/accel sens and neutrals.
This is especially useful for gyro, as most people don't have a turntable to calibrate them. Gyro bias (neutral) is estimated, so that is fine at zero..
You are advised to calibrate the accel neutrals though...
But you always need to calibrate the mag (hard and soft iron calibration). You can't set any default values here as this depends on how the surrounding materials affect the mag reading.
compiling without any of the old calibration stuff like MAG_XY_SENS (I
can't remember the exact definition name) it fails to compile.
If something fails to compile, please post the actual errors! Although in this case it is clear that it won't work without mag sens and neutral defines.
For now, I'm just copying my old Aspirin calibration file for it to work
(and it works fine this way.) Also, Aspirin 2.1 doesn't have a target
makefile, is it ok to use the 2.0 makefile?