In Some cases, Cisco phones would fail to upgrade from the Cisco Call Manager TFTP server due to tftp DL timeout when the phone and the Call manager server running the TFTP service are separated by the WAN. The issue is being tracked in the following defect: CSCto31256.
The Workaround is to use a 3rd party tftp server local to the phone. Here is the process to upgrade 79xx phone’s firmware using a TFTPd32:
1. Download a tftp server application, a good free application is tftpd32 and it can be downloaded from here
2. Download the phone’s firmware from the Software download page on cisco.com
You will need to download the .zip format, in this example, I will be using a 7945 phone.
4. Update the configuration of the phone with the load name that you need to upgrade to.
Then download the config file from the Call Manager TFTP server. You can use the Command Prompt in Windows to download it by typing:
tftp -i <tftp server ip> get SEP<Phone’s MAC>.cnf.xml
5. Extract the file downloaded in step 2 in the TFTP directory with the config file of the phone that was downloaded in step 4.
6. On the phone, go to Settings -> Network Configuration -> IPv4 Configuration -> Alternate TFTP, then hit **# to unlock the config page, and make sure that the Alternate TFTP option is set to YES.
7. Point the phone to the your TFTP server by editing the TFTP Server 1 option on the same menu.
8. Reset the phone.