What is firmware?
Firmware is defined as a computer program that is hard-coded into the hard drive and contains its basic operational storage programming. Another way to think of it is that firmware is a software middleman that allows your hardware to talk to software (i.e., Windows operating systems, etc). For a hard drive, firmware is a program that governs the behavior and factory settings, even the identity, of that drive. Any drive that comes out of the factory and is in use in a computer or server has firmware installed on it from the factory.
Performing a firmware update can be risky by itself even in the best of situations. For example, a power outage during a firmware update carries a very good possibility of ruining the drive. External, Serial ATA, and ATA drives are not designed for field firmware updates by end users.
Very often, system or device driver issues cause symptoms that are incorrectly called "firmware problems."
How to update firmware