In this guide
What firmware is
Firmware is the quiet software that lives inside hardware, shaping how nearly every connected device behaves. The name itself captures its nature: it is "firm" — more permanent than ordinary software, yet not as fixed as the physical hardware. Firmware is a set of instructions built into a device that tells it how to operate at the most basic level. When you use a printer, a router, a camera, or a smart speaker, firmware is running inside it, orchestrating the device's fundamental behavior. Understanding firmware illuminates a layer of technology that is usually hidden but frequently referenced.
Where firmware lives
Firmware is stored in a device's non-volatile memory — a type of memory that retains its contents even when the device is powered off. This is why a device "remembers" how to operate the moment it is switched on, without needing to load instructions from elsewhere. Because firmware resides in the device itself, it is always present and always available, forming the foundation on which all of the device's other behavior is built. This storage location is part of what distinguishes firmware from software that is loaded fresh each time it runs.
Firmware at startup
Firmware's first and most important job happens the instant a device powers on. Before anything else can occur, firmware initializes the device's hardware components, bringing them to a known, ready state. It checks and prepares the physical parts of the device, sets up internal systems, and readies the device to perform its function or to communicate with other systems. This startup role is why a device can begin operating on its own, seemingly "knowing" what to do before any external software is involved. Firmware is, in effect, the device's innate knowledge of itself.
Firmware vs. software and operating systems
It is easy to confuse firmware with the software and operating systems users interact with, but they occupy different layers. Ordinary software — applications — runs on top of an operating system and is loaded when needed. An operating system is a large, general-purpose layer that manages a device's resources and provides services to applications. Firmware sits below these, closest to the hardware, and is more specialized and stable. Whereas applications change frequently and operating systems are updated regularly, firmware is engineered to change rarely, because it operates so close to the physical device. Our guide on printer drivers discusses a related layer — drivers — that bridges operating systems and devices, distinct from firmware inside the device itself.
Why manufacturers release updates
Although firmware is stable, it is not necessarily permanent. Manufacturers sometimes release firmware updates, and understanding why helps explain their purpose. A firmware update refines how the hardware itself behaves. It might improve compatibility with other systems, adjust internal logic, address edge-case behavior, or enhance how the device manages its low-level operations. Because firmware governs fundamental behavior, an update can meaningfully change how a device works. This is different from updating an application; it is more like refining the device's own inner workings.
How the update process works
Updating firmware is a careful, deliberate operation, precisely because firmware sits so close to the hardware. Conceptually, the process replaces the existing firmware in the device's non-volatile memory with a new version provided by the manufacturer. Because this affects such a foundational layer, firmware update processes are designed with reliability in mind, taking care to ensure the update completes correctly. This conservative design reflects firmware's importance: a device depends on its firmware to function, so the process of changing it is engineered to be dependable. Knowing this explains why firmware updates are treated with more caution than ordinary software updates and why they are released less frequently.
Key takeaways
- Firmware is built-in software that governs a device's most basic behavior.
- It is stored in non-volatile memory, so it persists when the device is powered off.
- At startup, firmware initializes hardware and prepares the device to operate.
- Firmware sits below applications and operating systems, closest to the hardware, and changes rarely.
- Manufacturers release firmware updates to refine how the hardware itself behaves.
- The update process is engineered conservatively for reliability, given firmware's foundational role.