Firmware

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Firmware is commonly stored in an EEPROM or Flash memory, which makes use of an I/O protocol such as SPI. WD Blue WD5000LPVX - controller - Winbond 25X20CLVIG-0182.jpg
Firmware is commonly stored in an EEPROM or Flash memory, which makes use of an I/O protocol such as SPI.

In computing, firmware is software that provides low-level control of computing device hardware. For a relatively simple device, firmware may perform all control, monitoring and data manipulation functionality. For a more complex device, firmware may provide relatively low-level control as well as hardware abstraction services to higher-level software such as an operating system.

Contents

Firmware is found in a wide range of computing devices including personal computers, phones, home appliances, vehicles, computer peripherals and in many of the digital chips inside each of these larger systems.

Firmware is stored in non-volatile memory – either read-only memory (ROM) or programmable memory such as EPROM, EEPROM, or flash. Changing a device's firmware stored in ROM requires physically replacing the memory chip – although some chips are not designed to be removed after manufacture. Programmable firmware memory can be reprogrammed via a procedure sometimes called flashing . [2]

Common reasons for changing firmware include fixing bugs and adding features.

History and etymology

Ascher Opler used the term firmware in a 1967 Datamation article, as an intermediary term between "hardware" and "software". Opler projected that fourth-generation computer systems would have a writable control store (a small specialized high-speed memory) into which microcode firmware would be loaded. Many software functions would be moved to microcode, and instruction sets could be customized, with different firmware loaded for different instruction sets. [3]

As computers began to increase in complexity, it became clear that various programs needed to first be initiated and run to provide a consistent environment necessary for running more complex programs at the user's discretion. This required programming the computer to run those programs automatically. Furthermore, as companies, universities, and marketers wanted to sell computers to laypeople with little technical knowledge, greater automation became necessary to allow a lay-user to easily run programs for practical purposes. This gave rise to a kind of software that a user would not consciously run, and it led to software that a lay user wouldn't even know about. [4]

As originally used, firmware contrasted with hardware (the CPU itself) and software (normal instructions executing on a CPU). It was not composed of CPU machine instructions, but of lower-level microcode involved in the implementation of machine instructions. It existed on the boundary between hardware and software; thus the name firmware. Over time, popular usage extended the word firmware to denote any computer program that is tightly linked to hardware, including BIOS on PCs, boot firmware on smartphones, computer peripherals, or the control systems on simple consumer electronic devices such as microwave ovens, remote controls.

Applications

Computers

ROM BIOS firmware on a Baby AT motherboard AMI 486DX EISA BIOS 20051109.jpg
ROM BIOS firmware on a Baby AT motherboard

In some respects, the various firmware components are as important as the operating system in a working computer. However, unlike most modern operating systems, firmware rarely has a well-evolved automatic mechanism of updating itself to fix any functionality issues detected after shipping the unit.

A computer's firmware may be manually updated by a user via a small utility program. In contrast, firmware in mass storage devices (hard-disk drives, optical disc drives, flash memory storage e.g. solid state drive) is less frequently updated, even when flash memory (rather than ROM, EEPROM) storage is used for the firmware.

Most computer peripherals are themselves special-purpose computers. Devices such as printers, scanners, webcams, and USB flash drives have internally-stored firmware; some devices may also permit field upgrading of their firmware. For modern simpler devices, such as USB keyboards, USB mouses and USB sound cards, the trend is to store the firmware in on-chip memory in the device's microcontroller, as opposed to storing it in a separate EEPROM chip.

Examples of computer firmware include:

Updating the firmware of a Fuji Instax camera Firmware update Fuji Instax Liplay.jpg
Updating the firmware of a Fuji Instax camera

Home and personal-use products

Consumer appliances like gaming consoles, digital cameras and portable music players support firmware upgrades. Some companies use firmware updates to add new playable file formats (codecs). Other features that may change with firmware updates include the GUI or even the battery life. Smartphones have a firmware over the air upgrade capability for adding new features and patching security issues.

Automobiles

Since 1996, most automobiles have employed an on-board computer and various sensors to detect mechanical problems. As of 2010, modern vehicles also employ computer-controlled anti-lock braking systems (ABS) and computer-operated transmission control units (TCUs). The driver can also get in-dash information while driving in this manner, such as real-time fuel economy and tire pressure readings. Local dealers can update most vehicle firmware.

Other examples

Other firmware applications include:

Flashing

Flashing [6] involves the overwriting of existing firmware or data, contained in EEPROM or flash memory module present in an electronic device, with new data. [6] This can be done to upgrade a device [7] or to change the provider of a service associated with the function of the device, such as changing from one mobile phone service provider to another or installing a new operating system. If firmware is upgradable, it is often done via a program from the provider, and will often allow the old firmware to be saved before upgrading so it can be reverted to if the process fails, or if the newer version performs worse. Free software replacements for vendor flashing tools have been developed, such as Flashrom.

Firmware hacking

Sometimes, third parties develop an unofficial new or modified ("aftermarket") version of firmware to provide new features or to unlock hidden functionality; this is referred to as custom firmware. An example is Rockbox as a firmware replacement for portable media players. There are many homebrew projects for various devices, which often unlock general-purpose computing functionality in previously limited devices (e.g., running Doom on iPods).

Firmware hacks usually take advantage of the firmware update facility on many devices to install or run themselves. Some, however, must resort to exploits to run, because the manufacturer has attempted to lock the hardware to stop it from running unlicensed code.

Most firmware hacks are free software.

HDD firmware hacks

The Moscow-based Kaspersky Lab discovered that a group of developers it refers to as the "Equation Group" has developed hard disk drive firmware modifications for various drive models, containing a trojan horse that allows data to be stored on the drive in locations that will not be erased even if the drive is formatted or wiped. [8] Although the Kaspersky Lab report did not explicitly claim that this group is part of the United States National Security Agency (NSA), evidence obtained from the code of various Equation Group software suggests that they are part of the NSA. [9] [10]

Researchers from the Kaspersky Lab categorized the undertakings by Equation Group as the most advanced hacking operation ever uncovered, also documenting around 500 infections caused by the Equation Group in at least 42 countries.

Security risks

Mark Shuttleworth, the founder of the company Canonical, which created the Ubuntu Linux distribution, has described proprietary firmware as a security risk, saying that "firmware on your device is the NSA's best friend" and calling firmware "a trojan horse of monumental proportions". He has asserted that low-quality, closed source firmware is a major threat to system security: [11] "Your biggest mistake is to assume that the NSA is the only institution abusing this position of trust – in fact, it's reasonable to assume that all firmware is a cesspool of insecurity, courtesy of incompetence of the highest degree from manufacturers, and competence of the highest degree from a very wide range of such agencies". As a potential solution to this problem, he has called for declarative firmware, which would describe "hardware linkage and dependencies" and "should not include executable code". [12] Firmware should be open-source so that the code can be checked and verified.

Custom firmware hacks have also focused on injecting malware into devices such as smartphones or USB devices. One such smartphone injection was demonstrated on the Symbian OS at MalCon, [13] [14] a hacker convention. A USB device firmware hack called BadUSB was presented at the Black Hat USA 2014 conference, [15] demonstrating how a USB flash drive microcontroller can be reprogrammed to spoof various other device types to take control of a computer, exfiltrate data, or spy on the user. [16] [17] Other security researchers have worked further on how to exploit the principles behind BadUSB, [18] releasing at the same time the source code of hacking tools that can be used to modify the behavior of different USB devices. [19]

See also

Related Research Articles

<span class="mw-page-title-main">BIOS</span> Firmware for hardware initialization and OS runtime services

In computing, BIOS is firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process. The firmware comes pre-installed on the computer's motherboard.

<span class="mw-page-title-main">AVR microcontrollers</span> Family of microcontrollers

AVR is a family of microcontrollers developed since 1996 by Atmel, acquired by Microchip Technology in 2016. These are modified Harvard architecture 8-bit RISC single-chip microcontrollers. AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to one-time programmable ROM, EPROM, or EEPROM used by other microcontrollers at the time.

<span class="mw-page-title-main">Live CD</span> Complete, bootable computer installation that runs directly from a CD-ROM

A live CD is a complete bootable computer installation including operating system which runs directly from a CD-ROM or similar storage device into a computer's memory, rather than loading from a hard disk drive. A live CD allows users to run an operating system for any purpose without installing it or making any changes to the computer's configuration. Live CDs can run on a computer without secondary storage, such as a hard disk drive, or with a corrupted hard disk drive or file system, allowing data recovery.

<span class="mw-page-title-main">USB flash drive</span> Data storage device

A flash drive is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and usually weighs less than 30 g (1 oz). Since first offered for sale in late 2000, the storage capacities of USB drives range from 8 megabytes to 256 gigabytes (GB), 512 GB and 1 terabyte (TB). As of 2023, 2 TB flash drives were the largest currently in production. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and are thought to physically last between 10 and 100 years under normal circumstances.

udev is a device manager for the Linux kernel. As the successor of devfsd and hotplug, udev primarily manages device nodes in the /dev directory. At the same time, udev also handles all user space events raised when hardware devices are added into the system or removed from it, including firmware loading as required by certain devices.

Homebrew, when applied to video games, refers to software produced by hobbyists for proprietary video game consoles which are not intended to be user-programmable. The official documentation is often only available to licensed developers, and these systems may use storage formats that make distribution difficult, such as ROM cartridges or encrypted CD-ROMs. Many consoles have hardware restrictions to prevent unauthorized development.

<span class="mw-page-title-main">Dreambox</span>

Dreambox is a series of Linux-powered DVB satellite, terrestrial and cable digital television receivers, produced by German multimedia vendor Dream Multimedia.

System Management Mode is an operating mode of x86 central processor units (CPUs) in which all normal execution, including the operating system, is suspended. An alternate software system which usually resides in the computer's firmware, or a hardware-assisted debugger, is then executed with high privileges.

The boot ROM is a type of ROM that is used for booting a computer system. There are two types: a mask boot ROM that cannot be changed afterwards and a boot EEPROM.

<span class="mw-page-title-main">Das U-Boot</span> Open-source, primary boot the devices operating system kernel

Das U-Boot is an open-source boot loader used in embedded devices to perform various low-level hardware initialization tasks and boot the device's operating system kernel. It is available for a number of computer architectures, including M68000, ARM, Blackfin, MicroBlaze, AArch64, MIPS, Nios II, SuperH, PPC, RISC-V and x86.

<span class="mw-page-title-main">Brick (electronics)</span> Non-functioning electronic device

A brick is a mobile device, game console, router, computer or other electronic device that is no longer functional due to corrupted firmware, a hardware problem, or other damage. The term analogizes the device to a brick's modern technological usefulness.

In the context of free and open-source software, proprietary software only available as a binary executable is referred to as a blob or binary blob. The term usually refers to a device driver module loaded into the kernel of an open-source operating system, and is sometimes also applied to code running outside the kernel, such as system firmware images, microcode updates, or userland programs. The term blob was first used in database management systems to describe a collection of binary data stored as a single entity.

The Linux booting process involves multiple stages and is in many ways similar to the BSD and other Unix-style boot processes, from which it derives. Although the Linux booting process depends very much on the computer architecture, those architectures share similar stages and software components, including system startup, bootloader execution, loading and startup of a Linux kernel image, and execution of various startup scripts and daemons. Those are grouped into 4 steps: system startup, bootloader stage, kernel stage, and init process. When a Linux system is powered up or reset, its processor will execute a specific firmware/program for system initialization, such as the power-on self-test, invoking the reset vector to start a program at a known address in flash/ROM, then load the bootloader into RAM for later execution. In IBM PC–compatible personal computers (PCs), this firmware/program is either a BIOS or a UEFI monitor, and is stored in the mainboard. In embedded Linux systems, this firmware/program is called boot ROM. After being loaded into RAM, the bootloader will execute to load the second-stage bootloader. The second-stage bootloader will load the kernel image into memory, decompress and initialize it, and then pass control to this kernel image. The second-stage bootloader also performs several operation on the system such as system hardware check, mounting the root device, loading the necessary kernel modules, etc. Finally, the first user-space process starts, and other high-level system initializations are performed.

An electronic device or embedded system is said to be field-programmable or in-place programmable if its firmware can be modified "in the field", without disassembling the device or returning it to its manufacturer.

<span class="mw-page-title-main">PICkit</span>

PICkit is a family of programmers for PIC microcontrollers made by Microchip Technology. They are used to program and debug microcontrollers, as well as program EEPROM. Some models may also feature logic analyzers and serial communications (UART) tools.

<span class="mw-page-title-main">Huawei E220</span> Modem developed by Huawei

The Huawei E220 is a Huawei HSDPA access device (modem) manufactured by Huawei and notable for using the USB interface.

Proprietary firmware is any firmware that has had its use, private modification, copying, or republishing restricted by the producer. Proprietors may enforce restrictions by technical means, such as by restricting source code access, firmware replacement restrictions, or by legal means, such as through copyright and patents. Alternatives to proprietary firmware may be free (libre) or open-source.

<span class="mw-page-title-main">Read-only memory</span> Electronic memory that cannot be changed

Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications, such as video games, for programmable devices can be distributed as plug-in cartridges containing ROM.

A debug port is a diagnostic interface included in an electronic system or integrated circuit to aid design, fabrication, development, bootstrapping, configuration, debugging, and post-sale in-system programming. In general terms, a debug port is not necessary for end-use function and is often hidden or disabled in finished products.

In computing, a devicetree is a data structure describing the hardware components of a particular computer so that the operating system's kernel can use and manage those components, including the CPU or CPUs, the memory, the buses and the integrated peripherals.

References

  1. ↑ "W25X20CL Datasheet". Winbond . Retrieved 2024-08-30.
  2. ↑ "What is firmware?". 23 January 2013.
  3. ↑ Opler, Ascher (January 1967). "Fourth-Generation Software". Datamation. 13 (1): 22–24.
  4. ↑ "Introduction to Computer Applications and Concepts. Module 3: System Software". Lumen.
  5. ↑ Mielewczik, Michael (2000). "Firmware-Update. Mehr Speed und Sicherheit". PC Praxis (in German). 1/2000: 68.
  6. 1 2 "Flashing Firmware". Tech-Faq.com. Archived from the original on September 27, 2011. Retrieved July 8, 2011.
  7. ↑ "HTC Developer Center". HTC. Archived from the original on April 26, 2011. Retrieved July 8, 2011.
  8. ↑ "Equation Group: The Crown Creator of Cyber-Espionage". Kaspersky Lab. February 16, 2015. Archived from the original on December 2, 2015.
  9. ↑ Dan Goodin (February 2015). "How "omnipotent" hackers tied to NSA hid for 14 years—and were found at last". Ars Technica . Archived from the original on 2016-04-24.
  10. ↑ "Breaking: Kaspersky Exposes NSA's Worldwide, Backdoor Hacking of Virtually All Hard-Drive Firmware". Daily Kos. February 17, 2015. Archived from the original on February 25, 2015.
  11. ↑ "Shuttleworth Calls for Declarative Firmware". Linux Magazine. No. 162. May 2014. p. 9.
  12. ↑ Shuttleworth, Mark (March 17, 2014). "ACPI, firmware and your security". Archived from the original on March 15, 2015.
  13. ↑ "MalCon 2010 Technical Briefings". Malcon.org. Archived from the original on 2011-07-04.
  14. ↑ "Hacker plants back door in Symbian firmware". H-online.com. 2010-12-08. Archived from the original on 21 May 2013. Retrieved 2013-06-14.
  15. ↑ "Why the Security of USB Is Fundamentally Broken". Wired.com. 2014-07-31. Archived from the original on 2014-08-03. Retrieved 2014-08-04.
  16. ↑ "BadUSB - On Accessories that Turn Evil". BlackHat.com. Archived from the original on 2014-08-08. Retrieved 2014-08-06.
  17. ↑ Karsten Nohl; Sascha Krißler; Jakob Lell (2014-08-07). "BadUSB – On accessories that turn evil" (PDF). srlabs.de. Archived (PDF) from the original on 2016-10-19. Retrieved 2014-08-23.
  18. ↑ "BadUSB Malware Released — Infect millions of USB Drives". The Hacking Post. Archived from the original on 6 October 2014. Retrieved 7 October 2014.{{cite web}}: CS1 maint: unfit URL (link)
  19. ↑ Greenberg, Andy. "The Unpatchable Malware That Infects USBs Is Now on the Loose". WIRED. Archived from the original on 7 October 2014. Retrieved 7 October 2014.
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