How to enter code in HTC ATT Quickfire?
1. Turn HTC ATT Quickfire with a SIM card not accepted by the terminal, ie another operator.
2 If the SIM card has a PIN, enter it and press OK. If you have set a security code and press OK mark.
3 Then HTC ATT Quickfire asked RED code ("SIM lock code" or "unlock code SIM card").
4 Enter the unlock code and press OK. Sometimes you need to do Hard Reset [first saves important data (contacts, photos, etc..)].