You will need a TFP server to update the firmware.
- Obtain the latest firmware for your device from Cisco Support.
- Extract the archive and copy the *.bin file to spa.bin and place it in your TFTP servers root directory.
- In a web browser visit "http://<PHONE IP ADDRESS>/upgrade?tftp://<TFTP SERVER IP>/spa.bin
- Do not power cycle/reboot the phone it will automatically reboot once the firmware has been updated.
Please note the filename for the firmware must be named spa.bin otherwise the upgrade will fail.