I've started to work on the calibration feature. It is shaping up nicely and improves somewhat the accuracy of the measurements but I'm still not getting to the level of accuracy that the original unit boasted (i.e. 0.01V and 0.001A).

The unit is however already usable as is, the alternative firmware can receive commands by serial and exhibit good control of the device that makes it possible to use it just fine.

The buttons still do not work and I don't do a great job with the display for now but these are features for interactive work and my main goal is the serial control anyway.