Specifically the very last step with the button that clears out any saved JS.
You mentioned nrftool - did you connect directly to the board via SWD? If so you'll need to build without DFU_UPDATE_BUILD=1 and flash the resulting hex (as that'll include the bootloader)
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.
That all looks fine - did you flash the zip that's created with the steps from http://www.espruino.com/Puck.js#firmware-updates ?
Specifically the very last step with the button that clears out any saved JS.
You mentioned
nrftool
- did you connect directly to the board via SWD? If so you'll need to build withoutDFU_UPDATE_BUILD=1
and flash the resulting hex (as that'll include the bootloader)