I've been trying to get HGST SSD firmware updates for weeks...
The official support site does have firmwares available for some models but none of them are the ones I own. No option to register mine. Matter of fact the only drives I've been able to update were HP OEMs that were done in a SPP upgrade. The models I own can be picked up directly from sites like CDW so there have to be firmware updates available somewhere but I'm guessing it's got to be a paid support contract kinda thing.