Case in point: We update the HDDs and SSDs on our storage systems regularly. Every month there's new disk drive firmware coming out for various (OEM) drives. I

Case in point: We update the HDDs and SSDs on our storage systems regularly. Every month there's new disk drive firmware coming out for various (OEM) drives. I have never seen a disk fw update introduce new bugs. Firmware development works quite a bit differently than regular software development. There's usually no new "feature" that can possibly be added to a disk drive. It's not like you're suddenly getting a new desktop environment on it. But yeah, I have seen a handful of HDDs die during the mandatory power cycle because they wouldn't spin back up. And sometimes, disks fail at a higher rate after the firmware update, but that is not due to introduced bugs but rather because the error detection/reporting functionality has improved and is now reporting issues that it didn't before. For enterprise storage systems that is actually a good thing, because a predicted failure is always better than a sudden failure. Case in point: A few years ago, the HGST Cobra drives were leaking fluid from the motor onto the platters. There was nothing that could be done, so the firmware was updated to move the heads more (to prevent fluid buildup) and the error detection was changed to detect the slowed head movement and report that via sense codes. Of course that caused more early failures, but that's better than having a handful disks fail all at once, and the disks would have failed anyway at some point.