Seems you are saying that the DCI measure function returns overflow for the 3A and lower ranges.
Both front and rear. No connections and still get overflow.
However, the 10A range available on rear only, is somewhat functional.
To me, it sounds like a malfunctioning meter.
Firmware unlikely to help such a symptom.
Separate from DCI is the digitize current measure function. Does that still work for the 3A and lower ranges?