If you attempt to upgrade firmware AFTER entering phone into sipXconfig interface run this command
then follow these instructions.
Beyond adding an entry in the phone list for your Cisco phone and assigning a user to that phone, there are a few more steps you meed to make to this phone work.
Download and install SIP support for your phone from Cisco. You will need an account with Cisco.
Also in this package is a binary executable that needs to be placed in a specific location to be called from within the configuration server.
cp cfgfmt.linux /etc/sipxpbx/ciscoAta/cfgfmt
Perform the following steps on your Cisco 7905G and 7912G phones:
To change the Cisco logo on your phone
1. Edit your phone or phone group Software Upgrade settings with following values:
2. Send profiles to phone
3. To make your own logo, edit this file