Source note · Troubleshooting Cisco IP phones stuck upgrading firmware
Phones cannot be used for calls while their firmware is being upgraded.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Cisco Unified Communications Manager
- Subsystem
- upgrade
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 15 and SUs
- Checked
- 2026-10-02
Sources
- Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process) — Cisco Systems · tier 2 current vendor documentation · Upgrade IP Phone Firmware
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Cisco IP phones stuck upgrading firmware: source note cucm-phone-firmware-upgrade-troubleshooting-no-calls-during. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-phone-firmware-upgrade-troubleshooting-no-calls-during
BibTeX
@misc{warmtransfer-claim-cucm-phone-firmware-upgrade-troubleshooting-no-calls-during,
title = {Troubleshooting Cisco IP phones stuck upgrading firmware: source note cucm-phone-firmware-upgrade-troubleshooting-no-calls-during},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-phone-firmware-upgrade-troubleshooting-no-calls-during},
note = {Source note cucm-phone-firmware-upgrade-troubleshooting-no-calls-during, checked 2026-10-02}
}