Firmware Update: WD4000FYYZ

I am trying to figure out two things. How do I get the latest firmware and how to I update the drive? I have 3 drives that currently have version 01.01.K03 but one drive with K02. The drive needs K03 to work with my NAS. But I can’t find any firmware on the device page under the downloads section.

Usually there are no firmware updates for internal HDDs. They only do it if there is a common serious problem that needs a firmware fix but that rarely happens! Also I hope your NAS enclosure have adequate cooling because these drives run hot and loud. A WD RED would be more suitable for a NAS.