Firmware is a type of computer program that is inherent in the hardware device. An example of which is the microcontroller. As the name implies, this program is neither a software nor hardware. However, it does function like software wherein it executes a computer program through a microcontroller or microprocessor. On the other hand, it is also tied into a hardware device that it cannot function when separated from the device.

Firmware was initially used for micro-programs but was later recognized for its functionality that could potentially replace hardware at a low cost. Firmware is a content of the hardware device that can be programmed. Hence, it may consist of a language for the microprocessor, or different configuration setting. Today, there are several devices whose firmware can be updated, which undergoes an electronic process for modern systems. Meanwhile, other processes of updating are also done by replacing the storage medium that contains firmware.

A firmware is capable of exposing an external interface. Although some modems do not have direct access to a firmware, there are also those that are combined with the hardware that enables to elicit response from the host system.

Most machines that are now attached to a modern system are also equipped with their own special software. Hence, the firmware is stored within the device’s ROM in itself. But it was recently discovered by most manufacturers that it is cheaper to load the firmware from the host system. Hence, most computers nowadays are unable to function unless it is connected with the requisite firmware. A device driver is needed to handle the firmware load.

The following products by Apple are capable receiving firmware updates:

  • AirPort
  • Bluetooth
  • PowerBook
  • Power Mac
  • iSight
  • iMac
  • iBook
  • video cards
  • optical drivers such as DVD-ROM or CD drives

Oftentimes, a new or modified version of firmware is produced by a third party to either create new features or unlock functionalities that are hidden. There are several examples of them on several devices while others are done through homebrew games for consoles. Once it is penetrated, it allows access into general computing functions which are previously limited.

These hacks are free and done through open source software. Since most firmwares today are equipped with an update facility, hackers take advantage of this in order to let devices run or install themselves.