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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.
@fanoush
if you see the DFU START message after releasing button before the bar goes fully to the right and you don't see it in nrfConnect scan as DfuTarg device and see other devices then it indeed looks like something is wrong with bluetooth signal transmission because otherwise the software thinks everything works. and this is Nordic DFU bootloader, Espruino is not running at this time. If e.g. the 32khz crystal (that provides bluetooth timing) was broken or missing it would not even start.