not sure about that guide but you can do same thing by adding it directly to your board file, see one example here https://github.com/espruino/Espruino/blob/master/boards/DICKENS.py#L104
thx. apparently the documentation is a bit outdated
@fanoush 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.
not sure about that guide but you can do same thing by adding it directly to your board file, see one example here https://github.com/espruino/Espruino/blob/master/boards/DICKENS.py#L104