If you find that the micro:bit is not letting you update it after using one of the apps, it might be because the last Bluetooth flashing process was unsuccessful. 

This can cause the micro:bit to appear unresponsive, with a blank screen or a '+' symbol and not able to enter pairing mode.

If this happens, 

  1. Connect the micro:bit to a computer via USB 
  2. Open makecode.microbit.org in a new browser window
  3. Download and flash a simple program to the micro:bit
  4.  'forget' the micro:bit, in the Bluetooth settings on your mobile device and pair it again.

It should now work again with the app. For any further issues, please open a support ticket.

Keywords: stuck on + plus symbol, nothing on screen, plus, microbit displays cross, cross