Hello mgchoi,
BMI323 didn't support free fall feature. BMI270 supports free fall feature, you can find this feature in BMI270 Legacy firmware version.
BMI270 Legacy
Any motion, No motion, Significant motion detector
Orientation detector (Advanced Potrait-Landscape)
High-G, Low-G (Freefall) detector
Flat detector
Tap detection (Single, Double, Triple taps)
Smartphone Step counter and Step detector (Pedometer)
Activity change recognition
Still
Walking
Running
... View more