It would be useful to see the circuit diagram. Are the board you are using AND the ESP8266 module both being powered from the USB? It is possible that the USB isn't capable of delivering the sufficient current needed.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
It would be useful to see the circuit diagram. Are the board you are using AND the ESP8266 module both being powered from the USB? It is possible that the USB isn't capable of delivering the sufficient current needed.