"Firmware" is a term used to describe a combination of software and hardware. While software can be installed or removed without affecting any hardware devices, firmware is directly connected to a hardware device, and its information provides a way for other hardware or software to communicate with the device. Without firmware, most hardware devices would fail to function.
Which Devices Need Firmware?
Firmware can be found on almost any electronic device, from a a remote control to a DVD player or a games console. Any data or information recorded on a computer chip on it is considered firmware. The three most common types of firmware chip are read-only memory (ROM), programmable read-only memory and erasable programmable read-only memory. PROM and EPROM chips are designed to be updated if necessary.
Firmware, like software, is constantly being upgraded and remade by manufacturers in order to keep it up to date and compliant or add functionality. For example, without firmware updates, smartphone manufacturers would not be able to update the operating system beyond what their phones originally shipped with.
How to Upgrade
Firmware updates in latest technologies are often downloaded via the Internet so products such as iPhones can download their firmware updates automatically. Some devices will need to be upgraded via a CD or USB device, while others, such as TV boxes, will upgrade themselves using their connection to the content provider. Older devices, such as older TVs or DVD players that don't have the hardware capabilities to match latest developments, will run the same firmware for their life span.
Checking for Updated Firmware
Sometimes a manufacturer will release a firmware update and you might not find out about it -- which can be a problem in the case of significant security- or functionality-related updates. If your device doesn't check automatically for updates, it is a good idea to register for notifications from the manufacturer either using a registration form that comes with some devices or via their website.