After an update using the fwupdate update command where only the fallback image is updated, you might see an error that states that the update was unverified. An example of output is shown below:

# fwupdate update all -x metadata.xml

The following components will be upgraded as shown:
==========================================================
ID        Priority Action     Status      Old Firmware Ver.   Proposed Ver.  
    New Firmware Ver.   System Reboot    
------------------------------------------------------------------------------
------------------------------------------
sp        1        Check FW   Success     11.3.28.4.0         11.3.27.4.0    
    N/A                 N/A              
HOST MAY SHUT DOWN DURING SP FIRMWARE UPDATE!
Do you wish to process all of the above component upgrades? [y/n]? y
Updating sp:  Success

Verifying all priority 1 updates

Execution Summary
==========================================================
ID        Priority Action     Status      Old Firmware Ver.   Proposed Ver.  
    New Firmware Ver.   System Reboot    
------------------------------------------------------------------------------
------------------------------------------
sp        1        Validate   Failure     11.3.28.4.0         11.3.27.4.0    
    11.3.28.4.0         N/A              
        Error: Version verification failed.
ERROR: Version verification failed.

This issue can occur when updating SPARC system firmware if only the fallback mini-root image needs updating. If you encounter this issue when updating Oracle SPARC system firmware where only the fallback image is updated, you can safely ignore it. The update will have been successful even if fwupdate cannot verify it.