From Repair Mobile
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How to Enter Unlock Codes on BlackBerry Curve:
You must have a SIM card in your phone to complete these steps, I have found that this procedure works best with an AT&T or Cingular Sim card in the phone (can be active or inactive ). Make sure the phone is not displaying the low battery warning!
1. Power on More details [1] - thanks to cellphonerepair.org
