Do not power down the phone until it completes the factory reset process, and the main screen appears. http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/8811_8841_8851_8861/10_5/english/adminguide/P881_BK_C0632068_00_cisco-ip-phone-8811-8841/P881_BK_C0632068_00_cisco-ip...