'Uncaught InternalError: Timeout on I2C Write BUSY' after save()

Hi,

I think the issue you're seeing is that some stuff (the SSD1306 and NFC) will need initialising at power on.

What happens when you type save() is it saves the current state of the interpreter, but that doesn't include the external hardware.

There's more in-depth info on this here: http://www.espruino.com/Saving

But either you could add the lines:

function onInit() {
  // remove stuff if setup() was called previously
  clearInterval();
  clearWatch();
  // start up properly
  setup();
}

and save as you were doing, or you could use "save on send" which does what I think you're expecting happens now - which is basically to run all your code at boot time as if it were uploaded fresh each time.

The downside of the second option is you can't fiddle with the code while it's running and then re-save it, but you may not want to do that anyway.