@hypnos CP2014 controls the USB to serial connection.... COM port connection problems can result from other things: using the old driver (Windows), faulty USB cable, etc. However the CP2014 should NOT be so hot that you can't touch it and leave your finger there. Q - Is it that hot ? If it is, then yes perhaps don't use the battery with this unit. If the chip is super hot (and your COM port is working for other devices) you could also look to contact your supplier. I've tested lots of M5 units and use 4 regularly and have not had this problem. I also haven't heard of anyone else having this problem. If you get another M5 I would not at all expect this to happen again.