Abstract: A method for managing system firmware in a network attached storage (NAS) server comprises: synchronizing system firmware stored one or more of two or more hard disks (HDDs) and system firmware stored in a nonvolatile memory with each other; and confirming whether or not at least one valid HDD in which the system firmware is stored exists, when an HDD is replaced; and copying the system firmware stored in the nonvolatile memory into the replaced HDD, when it is confirmed that the valid HDD does not exist. In the method, when a watch dog timer is reset, the system firmware stored in the nonvolatile memory is synchronized, based on the system firmware stored in the HDD, by confirming whether or not the system firmware of the HDD and the system firmware of the nonvolatile memory are synchronized with each other.