We have some never-used 7961 phones going into a site that has been operational for some time. We set the phones up at the main site and made sure they were working correctly before taking them to the remote location. What's odd is that when we plug the phones in at the remote site, they look like they've registered, they get their DN and they can make and receive calls. However, they display UTC time, don't have the complete list of all of the CUCM servers they're supposed to know about, and if you go into their web pages there are other pieces information that are missing. A TFTP trace in RTMT seems to show that the TFTP transfer isn't completing. This seems to be site specific because we moved a working phone from one spot at that location to another today and now it's showing the same symptoms.
We've looked at ACLs on the switch to which all of the phones are connected and there is no QoS. They're getting the right TFTP server in DHCP. Furthermore, if we reset the phones back to factory defaults they are able to download all of the firmware files.