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.

Thanks for your reply, I can't reload the Factory Test because the computer can't detect the COM port when I connected the device by USB cable, I guess the board already have something defected.

Refer to your picture, the heat is mainly come from the CP2014, do you have any idea what's wrong?

I will still order some M5Stack but very hesitate to use the battery even it is one of the big reason I love this device.. That super heat may cause big trouble if the board have something wrong (or I do something wrong....) : (

I've only had the M5 heat up from one sketch that I tried.... was the Oscilloscope sketch and audio had not yet been disabled and the speaker was highly active.... was quickly fixed and no heatup after that.

When u said "and seems I can't detect the COM for this device anymore.." do you mean you can't establish a connection to the M5 using the USB connection ? And that it no longer appears on your COM port ? It should still connect with the bottom module disconnected.

(With the bottom module connected if necessary...) You could try loading a basic sketch (Factory Test) and see if it is still heating up.

Can you identify any specific area of the unit that the heat is coming from ?

Here is a picture of the two different M5 models: