Are you running the latest Espruino firmware? There was a huge improvement with version 2v06.
https://github.com/espruino/Espruino/blob/47d22f82e1c5b325f62bdccafb324553dcff7655/ChangeLog#L230
@MaBe started
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.
Are you running the latest Espruino firmware? There was a huge improvement with version 2v06.
https://github.com/espruino/Espruino/blob/47d22f82e1c5b325f62bdccafb324553dcff7655/ChangeLog#L230