: This specific error code in the QNAP ecosystem indicates a failure during the firmware update process, which may require a manual download and installation. Steps to Resolve Download and Update Issues
What can I do if the firmware update fails with FW004 error? - QNAP
The term "u221 004" is commonly associated with firmware versioning or error codes in the context of direct-attached storage (DAS) and network-attached storage (NAS) systems. Specifically: