Source note · Troubleshooting Cisco IP phones stuck upgrading firmware
In the 8800 startup sequence the phone loads the firmware image stored in flash, then requests the CTL file, then the ITL file, and only then requests its configuration file from TFTP.
Checked 2026-10-02
The phone requests the ITL file after it requests the CTL file.
- Vendor
- Cisco
- Product
- Cisco IP Phone 8800 Series
- Subsystem
- phone startup
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- Cisco IP Phone 8800 Series Administration Guide for Cisco Unified Communications Manager - Technical Details — Cisco Systems · tier 2 current vendor documentation · Phone Startup Overview (steps: Load the stored phone image; Request the CTL file; Request the ITL file; Request the configuration file)
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Cisco IP phones stuck upgrading firmware: source note cucm-phone-firmware-upgrade-troubleshooting-boot-order. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-phone-firmware-upgrade-troubleshooting-boot-order
BibTeX
@misc{warmtransfer-claim-cucm-phone-firmware-upgrade-troubleshooting-boot-order,
title = {Troubleshooting Cisco IP phones stuck upgrading firmware: source note cucm-phone-firmware-upgrade-troubleshooting-boot-order},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-phone-firmware-upgrade-troubleshooting-boot-order},
note = {Source note cucm-phone-firmware-upgrade-troubleshooting-boot-order, checked 2026-10-02}
}