Nano S firmware 1.4 Update problem

I have problem trying to instal firmware 1.4 nano S . I follow a step-by-step all the installation but now my nano S get stuck displaying Update , I plugging unplugging many time , still update in the display . The app manager ask me to enter the PIN . I cannot ,,,"Update" is freezer on the display. I sent email to customer service but no answer yet. Anybody with the same problem?