Firmware is the permanent software or code embedded in electronic devices or hardware components to control their functionality. Overall, firmware serves as the foundational software layer that enables hardware components and devices to operate effectively, providing control and functionality necessary for their intended purpose.
There are three levels of firmware:
- Low-level firmware. Usually stored in non-volatile memory chips, and it cannot be rewritten or updated.
- High-level firmware. Deployed in flash memory chips, high-level firmware comes with more complex instructions and allows updates.
- Subsystems. Semi-independent devices which are part of a more extensive system. Sybsystem firmware is embedded in CPUs, flash chips, and LCD units.
Firmware can also be divided into two types:
- BIOS. Embedded in a chip in a computer’s motherboard, it issues instructions that allow the device’s operating system to load.
- UEFI. Unified Extensible Firmware Interface (UEFI) is a new generation of firmware and a replacement for BIOS. Its advantages are greater security during boot.