On CUCM (via CLI or OS Administration):
file list tftp XMLDefault*
If missing, generate a fresh one via CUCM Administration:
You downloaded a repack from a forum. The phone continuously shows "Downloading xmldefault.cnf.xml...requesting...Done...rebooting."
Diagnosis: The XMLDefault.cnf.xml contains a <callManagerGroup> with an IP that the phone cannot ping, or the firmware version in the XML does not match the actual firmware on the flash. cisco ip phone downloading xmldefault cnf xml repack
Fix: Open the repack’s XMLDefault.cnf.xml in a validator. Look for:
utils service restart Cisco Tftp
On the phone: Settings > Unregister > Restart or simply unplug for 30 seconds.
The Issue: The phone has no entry in the Cisco Unified Communications Manager (CUCM). It asks for its specific file, fails, and falls back to XMLDefault.cnf.xml. If this file is missing or misconfigured on the TFTP server, the phone hangs. On CUCM (via CLI or OS Administration): file
Solution:
In some lab or recovery scenarios, you may need to repack manually. Cisco does not recommend manual editing, but you can force a rebuild:
Cisco phones can run either SCCP (Skinny) or SIP firmware. If you use a SIP repack on an SCCP phone, you will see "Downloading xmldefault.cnf.xml" followed by "Error: Invalid XML parse" and a reboot loop. If missing, generate a fresh one via CUCM
Solution: Re-flash the phone with the correct firmware type before applying the repack. For the 7940/7960 series, this requires a special .bin load.
Environment: CUCM 12.5, 200 phones (mostly 8845).
Symptom: Every morning at 8 AM, 30 phones reboot and fail to register, logs show "repack XMLDefault.cnf.xml".
Investigation: TFTP server CPU was 100% due to a backup job running simultaneously.
Root cause: TFTP service timed out while reading phone-specific files → served fallback → found default file outdated → repacked.
Resolution: Rescheduled backup, increased TFTP cache timeout, and synced all configs. The repack messages disappeared.
The phone will download XMLDefault.cnf.xml, realize it needs a specific SEP file, download that, and then register.