If you are using Cisco phones on third-party platforms (like Asterisk, FreePBX, or 3CX), you must manually create and "repack" the XML configuration files. A single formatting error will cause a download loop.
If the phone successfully downloads the XML file but reboots continuously without applying the firmware, double-check that the loadInformation tag in your repacked XML file identically matches the .loads file name.
The most frustrating issue is a . The phone repeatedly requests XMLDefault.cnf.xml and fails to move forward. A classic cause, detailed in the Asterisk community, is a non-RFC-compliant TFTP server. Some TFTP servers (like the old Debian tftpd ) return an error code 0x00,0x00 ("Not defined") instead of the required 0x00,0x01 ("File not found") when a file is missing. The phone ignores this ambiguous code and retries the request indefinitely.
If the load name is incorrect, change it to a known stable firmware version, save the configuration, and click if necessary. Step 5: Perform a Hard Factory Reset cisco ip phone downloading xmldefault cnf xml repack
Update Cisco IP Phone Firmware through Third-Party TFTP Server
When a Cisco IP phone gets stuck during the boot process with the message "Downloading XMLDefault.cnf.xml," it indicates a crucial failure in the phone’s initialization sequence. The phone is successfully contacting a TFTP server but cannot retrieve the necessary configuration file, or the file is malformed. This scenario is particularly common when upgrading firmware, migrating phones between systems, or setting up a new lab environment.
Validate if the file is actually reachable from the network using a third-party machine. If you are using Cisco phones on third-party
The <loadInformation> tag is the most important part. If the phone reads XMLDefault.cnf.xml and attempts to download the firmware defined there, but that binary file is missing from the TFTP server, the phone will fail and reboot.
: Configure the IP phone to use your local computer's IP as its "Alternate TFTP" server and restart the phone to trigger the download. Important Considerations 8861 software upgrading error - Cisco Community
If you downloaded a .zip package from Cisco and need to modify it or merge it with custom configuration files, use this repack workflow: The most frustrating issue is a
If the file is corrupted or missing, you can manually (recreate and re-upload) XMLDefault.cnf.xml on the CUCM TFTP server.
The phone screen flickered. For three seconds, it showed “Contacting DHCP.” Then, a miracle.
If you are migrating phones between clusters, the phone may be rejecting the new XMLDefault