Source note · Troubleshooting Cisco IP phones stuck upgrading firmware
Cisco attributes firmware downloads that fail part way through mainly to network issues or congestion, and notes that Cisco Webex Wireless Phone 840 and 860 support RFC 7233 range requests so they can resume a download.
Checked 2026-10-02
Devices that don't support RFC7233 are not affected by this feature.
- Vendor
- Cisco
- Product
- Cisco Unified Communications Manager
- Subsystem
- device firmware
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 15 and SUs
- Checked
- 2026-10-02
Sources
- Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Manage Device Firmware — Cisco Systems · tier 2 current vendor documentation · Potential Issues with Firmware Installs (table), partial-download row
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Cisco IP phones stuck upgrading firmware: source note cucm-phone-firmware-upgrade-troubleshooting-issue-partial-dl. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-phone-firmware-upgrade-troubleshooting-issue-partial-dl
BibTeX
@misc{warmtransfer-claim-cucm-phone-firmware-upgrade-troubleshooting-issue-partial-dl,
title = {Troubleshooting Cisco IP phones stuck upgrading firmware: source note cucm-phone-firmware-upgrade-troubleshooting-issue-partial-dl},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-phone-firmware-upgrade-troubleshooting-issue-partial-dl},
note = {Source note cucm-phone-firmware-upgrade-troubleshooting-issue-partial-dl, checked 2026-10-02}
}