Core Issue
The 4.0(1) version of 7914 firmware should be used whenever the Cisco IP phone is using firmware version 6.0(5) or later.
Resolution
With the Cisco IP phone 7914 expansion module, the user must upgrade to firmware release S00104000100 before installing the 6.0(5) or later Cisco IP Phone 7960/7940 phone load.
The installation program is named cmterm-7914-sccp.4-0-1.exe. Refer to Software Download - Cisco IP phone FW 7900 series (NON-SIP).