If your MAC address is '123123123abc', log into the console as 'root' and use something like this:
find /tftpboot -name '*123123123[aA][bB][cC]*'
That should give you every file that's associated with that phone. Just like with SCCP-B, the MAC address of the phone is the factor that makes the thing work. You can do something like the following to find references in your '/var/log/messages' file:
grep '\123123123[aA][bB][cC]' /var/log/messages
Once you find these references, you can validate that the Sangoma specific settings in the DHCP server are correct.