A full factory reset is the only way to reset the admin password. Since the factory reset option in the menu's is only accessible with the admin password a more complex process is required.
- Power cycle the phone and watch for the message “Starting application, press Cancel to interrupt” to be displayed, and then quickly select the Cancel button as this menu will only appear for a brief moment.
- At the Welcome screen a countdown timer will begin. Press and hold the About menu to locate and record the MAC address (or just flip the phone upside-down and look at the label on the bottom of the device).
- Release the About key to return to the Welcome menu and before the timer expires press and hold the number 1, 3, and 5, simultaneously on the dial pad for a few seconds until and a new screen should appear prompting for the password to reset the phone.
- Enter the device’s MAC address as the password and then select OK to reset the phone. This will wipe settings exactly as described earlier in this article and in doing so will return the administrator password to the default value of "456" (this gets changed to "654" following an update in a later step) allowing access back into the device to be provisioned again.
- When the phone has finished resetting you may follow the instructions from the document in this link to re-provision the phone.