Unbricking Cisco IP phone

Original text

Core Issue

After the default Skinny Call Control Protocol (SCCP) firmware of the 7912G IP phone is changed to Session Initiation Protocol (SIP) firmware and the IP phone is powered on, these issues occur:

This indicates that the phone firmware is corrupted.

Resolution

If the menu and hold buttons are lit red and green respectively, the phone is in recovery mode. It is possible to return the phone to an operational state.

Complete these steps in order to attempt to recover the phone:

1. Connect a PC to the same network as the phone.
2. Use a network sniffer in order to verify if the phone is operational.

Does the phone transmit any IP packets or request any files from a Trivial FTP (TFTP) server?

Yes The phone is operational. Proceed to step 3.
No The phone is no longer usable and can not be recovered.

3. Look at the network sniffer log and note this information used by the phone:

4. Put requested software image file on the TFTP server from which the phone requests it. The phone requests the last software image file that it downloaded or attempted to download, if the information is available. Or it requests its default recovery software image file.

     Phone  Recovery Software Image Filename
     ----------  --------------------------------
     Cisco 7902  cp7902r.zup
     Cisco 7905  ldragonr.zup
     Cisco 7912  cp7912r.zup
     ----------  --------------------------------

It is recommended that all the recovery files be copied to the primary and secondary TFTP servers specified in the Dynamic Host Configuration Protocol (DHCP) options in order to facilitate automatic recovery of the phones.

5. Reboot the phone. If the phone is not in a reboot cycle, disconnect and reconnect the power adaptor, or if inline power is used, disconnect and reconnectthe Ethernet cable.

6. Verify the phone is functional. The menu and hold buttons must no longer be lit.

7. Re-configure the phone, as needed. If TFTP was originally used to configure the phone, it is possible that the phone does not require manualre-configuration. In this case, the phone downloads the necessary configuration files from the TFTP server and automatically configures itself.

Note: If encryption was previously used on the Cisco 7905 or Cisco 7912, it is necessary to re-enter the encryption key into the phone.

Download the recovery software image file for 7905.
Download all 7905 tools
Download the Cisco TFTP server.