Hi, hope someone can help out.
We developed a problem with our 7940 IP Phones. We're on CUCM 22.214.171.1240-13. Recently when our users who use extension mobility log on/off the phone resets and then complains that the TFTP file cannot be found.
We have 6 servers (2 per site) in our cluster and if we change the TFTP option in DHCP to another site it seems to work. We also did a "show active version" on the CLI and found that there wasn't a .cop file for the 7940's. I added one recently and it seemed to spring back to life.
However it's happening again, and changing the DHCP option is no longer working.
Though the symptoms you are describing are not matching up exactly at first sight, I would definitely move away from this release due to CSCso93220 (dbnotify client removed, unable to reset phones). Updates for going up to 6.1(5)SU3 can be found here. Note for 6.1(5)/6.1(5)SU you need to do a 2 stage upgrade with an intermediate upgrade to a release between 6.1(3) and 6.1(4a)SU2 as stated in the compatibility matrix.