A new build is now available at https://github.com/espruino/EspruinoBui ... er/ESP8266 which hopefully addresses the issue of no callback when either a bad AP password or a bad AP SSID was supplied. If all has gone well, the callback will now be called in these instances and the `err` parameter will not be null and contain a reason description.
To know exactly which build you are using, see the README.md at the builds page to learn how to find "BUILD_DATE" and "BUILD_TIME". Please don't hesitate to post back if you still have problems or questions ... we are very much here to help as we can.