Espruino Wifi very hot / broken

Espruino WiFi can draw in the 350mA range for very small periods of time when connecting to WiFi, however if you're running the board from a standard 5v USB voltage source when nothing is connected and no code is running and you're still getting a 350mA power draw then something is very wrong.

Is the WiFi still connected into your circuit? The main culprits would be:

• you're somehow putting more than 3.3v onto the 3.3v line (it could be shorted to 5v?)
  
• you're drawing a lot of power from the 3.3v line so the on-board regulator can't maintain 3.3v (350mA is about the max it's rated for, so that could explain it)
  
• you're putting more than 5v on a GPIO input (all the Wifi's inputs should be 5v tolerant)
  
  

Which part of the board is getting hot? The little 3-legged regulator, or the STM32 chip itself? I have had one chip (on an ST discovery board) that did as you explain - getting very hot - and that was I believe caused by noise on the power supply/GPIO lines. I was using it in the engine of a car, and the electrical noise down the lines was far too great.