HI!
I have icm20648 + external custom compass connected over master i2c bus.
Everything seems to setup well (DMP does run, I2C master reads external compass) and correct data is received by icm20648 ( as per contents of EXT_SLV_SENS_DATA_00+ registers).
The problem is MAG_QUAT algorythm of DMP produces only roll and tilt data... no yaw at all! This means, that the data doesn't change when I turn device around Z axis... while Y and X updates quaternion data, received from DMP.
Any clues?