UCM Zeroconfig GRP2604


I am trying to add a few GRP2604 phones to my system. I went to zeroconfig->Model Update and uploaded the pack for the GRP2604 and zeroconfig does now correctly identify the phone model number. However, the UCM does not appear to write configurations out to the phone. In fact it appears the UCM is not communicating with the phone at all, as hitting the reboot button does not work at all.

I can manually connect the phones to the UCM sip accounts and this works, but this will be a tedious process. Is there any way to configure them via the UCM zeroconfig