I have just upgraded some bms boards to V4.4 and 2 of the boards were showing incorrect voltage of about 4.5v instead of about 3.37v, I have recalibrated back to correct readings and also these same two boards showed no readings of temperature, just wondering about any pointers as to start to fault find these two boards ?
I assume you reloaded the faulty boards firmware. Then I would go for a visual inspection of soldering and right placement of components. Then measure some voltage values in the circuit and compare them with measurements of a working board. If above doesn’t unveil any problems replace the attiny