Do you mean upgrade the phone load? If yes, then try upgradign to the latest phone load that is 8.0.4 SR2 that can be found in the following link:
http://www.cisco.com/cgi-bin/tablebuild.pl/ip-7900ser
cmterm-7940-7960-sccp.8-0-4.exe
7940/7960 IP Phone load - Compatible CCM Versions: 3.3, 4.0, 4.1, 4.2
The installation instructions are in the Readme file in the same link:
When using Cisco CallManager Release 5.0 or later
For Cisco CallManager 5.0, you must do all software installations and upgrades by using the Software Upgrades menu options. The system can upload and process only software that Cisco Systems approved. You cannot install or use third-party or Windows-based software applications that you may have been using with a previous version of Cisco CallManager with Cisco CallManager 5.0.
Using your web browser, login to the Cisco IPT Platform Administration web page
Under the Software Upgrades menu, select Install/Upgrade.
Fill in the appropriate values in the Software Location section for the file you downloaded above, and click Next.
In the Available Software drop-down box, select the file you downloaded above, and click Next.
After validating the MD5 has the correct value, click Next.
In the Warning box, verify you have selected the correct firmware, then click Install.
Check that you received a Success message.
When Using Cisco CallManager earlier than Release 5.0
Login to the console of the CallManager Server where you downloaded the installer.
Note the location where you saved the downloaded file.
Double-click the file to start the installation.
In the Welcome window, click Next.
In the License Agreement window, click Yes.
If a Read Only File Detected window pops up, click Yes.
After the installation finishes, click OK.
Reset all corresponding devices.
Cisco IP Phone Model 7940/7960 Alternate Firmware format
The Cisco IP Phone Model 7940/7960 Firmware version 8.0(4) is also supplied in a zip file, as an alternative in case a Cisco CallManager is not available to run the executable installer program. The name of this file is cmterm-7940-7960-sccp.8-0-4.zip.
After unzipping the firmware files, they should be manually copied to the appropriate directory on the TFTP server.
