Firmware

Every electronic device needs instructions on what to do with the power, the buttons, and the sensors. In a computer, these instructions come from programs that you install and delete yourself. With a washing machine, a remote control, or a router, it's different: there, the program is permanently lodged inside the device, in a memory chip on the circuit board. This exact permanently built-in program is called firmware. The name is a play on words: it sits between the hard hardware, meaning the electronics, and the freely exchangeable software. You can modify firmware, but usually only through a special procedure specified by the manufacturer.

Why a device without it is just a piece of plastic

Firmware determines what a device can do. A digital camera and a phone sometimes have very similar image sensors. Yet how good the photos look still depends heavily on how the firmware processes the sensor's readings. The same chip can therefore deliver good results in one device and mediocre results in another.

Because firmware sits so close to the electronics, bugs there are especially unpleasant. A crashed phone game you simply close. Faulty firmware, on the other hand, can cause a device to no longer turn on at all. In tech circles, such a device is then called a brick: it still has weight, but no function anymore.

Firmware is also central to security. Whoever can manipulate it controls the device below all other protective measures. A virus scanner in the operating system often sees none of it. That's why modern devices check with digital signatures before starting up whether their firmware is unaltered and truly comes from the manufacturer.

From the memory chip to the update

The firmware resides in flash memory, a chip that retains data even without power. When switched on, the processor begins executing the commands stored there step by step. In simple devices, that's already everything: the firmware is at the same time the entire program. In more complex devices, the firmware only starts the first stage and then loads a complete operating system.

A firmware update replaces the contents of this memory with a new version. The device downloads the file, checks its signature, and then writes it into flash memory. This exact moment is critical, because a power outage in the middle of writing can render the device unusable. Many manufacturers therefore build in two memory areas: if the new one fails, the device starts up again with the old one.

A common misconception is equating firmware with the operating system. Android on a phone is an operating system and manages apps, storage, and the screen. The firmware beneath it controls the individual components, such as the radio chip or the battery controller. Both layers work together, but are developed separately and often updated separately.

Where firmware shows up in the news and in everyday life

Firmware becomes most visible when a device updates it. The router blinks and is unreachable for a few minutes. The headphones receive a new version via the phone app and suddenly the noise cancellation works better. Car manufacturers deliver new firmware for engine control or charging electronics over the mobile network, with no visit to the shop required.

In business news, firmware often plays a role in recalls and security vulnerabilities. If a flaw is found in widely used router or camera chips, millions of devices are affected at a single stroke. One problem here: many cheap devices never receive another update after being sold. They remain on the network for years with the known vulnerability.

Firmware is also becoming more important in artificial intelligence. Specialized chips for AI computations need control programs that utilize the computing units as efficiently as possible. An update can measurably increase the speed of such chips without anything changing in the hardware. For data centers, this is a direct cost factor, because the same purchase delivers more performance.