Field Notice: FN74417 - Cisco UCS 6454 Fabric Interconnects May Enter Reboot Loop During Firmware Upgrade to Release 4.3(6.250094) or Later - Configuration Change Recommended

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Updated:July 20, 2026
Document ID:FN74417

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Medium
Impact Rating:
Medium
First Published:
2026-Jul-20
Last Published:
2026-Jul-20
Revision:
1.0
Cisco Bug IDs:

Notice

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected


Affected Product Name Description Comments
UCS-FI-6454 UCS Fabric Interconnect 6454  
UCS-FI-6454-D-U UCS Fabric Interconnect 6454  
UCS-FI-6454-U UCS Fabric Interconnect 6454  
UCS-FI-6454= UCS Fabric Interconnect 6454  




Defect Information


Defect IDHeadline
CSCwu50054When customer tried to upgrade firmware on the 4th Gen FI to 4.3.x, the FIs go into a reboot loop with error message "UCSM image signature verification failed"

Problem Description


When upgrading Cisco UCS Fabric Interconnect Firmware on UCS-FI-6454 to firmware release 4.3(6.250094) or later, the Fabric Interconnect may enter a reboot loop and display the following error message: UCSM image signature verification failed.


Background


Certain Cisco UCS 6454 Fabric Interconnects that shipped from Cisco Manufacturing had the 6300 UCS Manager image installed instead of the 6454 UCS Manager image. This caused the Fabric Interconnect to go into a reboot loop during firmware upgrade. This applies only to certain units with specific serial numbers that were shipped from Cisco Manufacturing.


Problem Symptom


Cisco UCS Fabric Interconnects enter into a reboot loop with the following error message: UCSM image signature verification failed.


Workaround/Solution


Solution

To determine if a serial number is affected by this issue, see the Serial Number Validation section of this field notice. If the serial number is present, open a case with the Cisco Technical Assistance Center (TAC) for help resolving this issue.


How to Identify Affected Products


To determine if a serial number is affected, use Cisco UCS Manager or Cisco Intersight to retrieve the serial number and then see the Serial Number Validation section of this field notice.


Serial Number Validation


The Cisco Support Assistant (CSA) can help verify whether a device is impacted by the issue that is described in this Field Notice. To check the device, either enter the serial number in the CSA on the right side of this page or click the following URL: Cisco Support Assistant

Revision History


VersionDescriptionSectionDate
1.0Initial Release—2026-JUL-20

For More Information

For further assistance or for more information about this field notice, contact the Cisco Technical Assistance Center (TAC) using one of the following methods:

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