Firmware is defined as a category of software permanently embedded into a device’s read-only memory, which provides instructions on how the device is supposed to operate and minimizes hardware-level security vulnerabilities.
Firmware, essentially, refers to software embedded in a piece of hardware. It enables the most basic of devices to function. It is usually stored on a read-only memory (ROM) chip, preventing it from getting accidentally erased while remaining close to the device’s metal. End-users can only delete or modify firmware using special programs. And it stays on those devices whether it is on or off.
A firmware in a device can bypass its operating systems, application programming interface (APIs), and device drivers to provide the machine with instructions and guidance that enable it to perform basic tasks, communicate with other devices, or function as intended. Firmware is distinct from software and middleware since it employs a microcode at a lower level that deploys machine instructions.
How does firmware work?
Firmware is the first part that runs when a device is powered on. It sends instructions for execution to the device’s processor. For simple devices such as remote controls, the firmware works continuously as there is no software to replace it. In more complex devices, such as computers, multiple firmware sets interact to achieve a common goal, such as loading their operating systems.
Types of firmware
There are three types of firmware:
- Low-level firmware: These cannot be modified or altered since they are considered as integral hardware elements. They are stored on nonvolatile memory chips such as ROM and programmable ROM (PROM).
- High-level firmware: These forms of firmware often have higher levels of instruction complexity than low-level firmware, bringing them closer to the realm of software than hardware. They are used in conjunction with flash memory chips to make upgrades possible.
- Subsystem: They are parts of a more extensive system that can work independently. It often looks like its device because the microcode for this firmware level is built into the central processing unit (CPU), the liquid crystal display units (LCD), and the flash chips. Also, it is like high-level firmware in terms of operation.
The firmware parts of a personal computer (PC) are just as important as the operating system (OS). But, unlike an OS, firmware can’t automatically fix problems that are found after the unit has been shipped. A personal computer’s basic input/output system (BIOS) is an example of a firmware component. The BIOS lets the PC’s operating system (OS) talk to keyboards and other connected devices.
Firmware in cars makes it possible for systems like computer-controlled antilock brake systems and computer-controlled transmission control units to work well. Firmware updates for consumer products like portable music players add new file formats that can be played. Others get better features, like graphical user interfaces (GUIs) or longer battery life.
Understanding firmware updates
A firmware update may be considered a software patch that improves the functionality of a device without necessitating any physical changes. The frequency of updates is dependent on the manufacturer. The purpose of updating the firmware is to enhance the user experience without adding new features and minimize bug fixes and the need for device repairs. One can also fix security vulnerability issues in hardware through firmware updates.
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Critical Components of Firmware Architecture
Firmware architecture contains six essential components – i.e., the OS, the kernel, device drivers, the chipset, basic input/output system (BIOS), and application code. Let us discuss these firmware components in detail:
1. Operating system (OS)
An operating system is a program that provides standard services for computer programs and manages its hardware and software resources. It allows resource sharing to allow multiple processes to run simultaneously without knowledge of each other’s existence. A boot program helps load it onto a computer, then performs its managing functions. Examples of OS include Windows and Linux, which both include firmware.
A kernel is a part of an OS software with complete control over the system. It facilitates communications between hardware and software components. It manages hardware resources such as memory, CPU, and input/output devices. It also handles conflicts regarding resource allocation and optimizes the resources.
3. Device drivers
Device drivers are programs that enable interaction with hardware devices. Without them, the hardware device cannot work. Device drivers are hardware-dependent and operating-system-specific. OS and other programs can interact with hardware through these drivers and act as translators.
ROM and flash memory chips hold the firmware; since they are non-volatile, manufacturers may use the chips to store the firmware’s permanent instructions. These chips can be rewritten and upgraded. Flash memory chips are reprogrammed during updates, while ROM integrated circuits need to be manually replaced.
Basic input/output system (BIOS) firmware is installed during production, providing the computer with instructions on performing basic tasks such as keyboard control and booting. One can also use it to identify and configure hardware such as computer hard drives.
6. Application code
An application code refers to a set of programs designed to carry out a specific function and run on top of a system code. The application code in firmware enables it to send instructions to devices to function or perform basic tasks. It allows for low-level control.
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Developers and engineers must follow a structured process to arrive at this firmware architecture. Here are steps for building firmware architecture:
- Identifying the requirements: Designers should identify the requirements needed before starting building firmware architecture. They should begin by defining the conditions and how they can fulfill them. A well-written statement should be definitive, meaning that it should be crystal clear and as brief as feasible. It must also be easy to test –; that is, it should be verifiable after a set of tests is carried out. The written statement should entail what the product does for the user.
- Distinguishing architecture from design and selection of elements: With the help of block diagrams, designers should represent the data obtained from the written statement above to establish the “how” with directional arrows. The data flow is shown on the system architecture diagram. It also enables the designers to choose specific elements to use depending on the product of their choice. These elements include processor platforms, languages, algorithms, operating systems, hardware device drivers and communication protocols, development tools, and or in-circuit emulation tools.
- Managing time: The architecture design should make meeting time deadlines set when performing various tests easier. Several products have a mix of soft-real-time, non-real-time, and hard-real-time requirements. Soft deadlines are the hardest to set in stone, test, and put into action. Less confusion can be caused by treating them as hard deadlines that one must constantly meet.
After figuring out when things need to be done, the first step in architecture is to show where real-time functions need to be, ideally on a central processing unit (CPU).
- The CPU also simplifies the analysis required to prove all deadlines were met.
- Designing for test: Designers should test every embedded system. A system test is done to ensure that the product meets the requirements. An integration test is done to ensure that some subsystems shown in the architecture diagrams work together and as expected. Finally, a unit test is done to ensure that the individual pieces of software planned for work as expected.
- Planning for change: During this stage, designers should understand the various changes that occur to their products. Then, they should design the firmware such that these modifications are simple to implement. If the software is well-architected, designers may handle feature diversity with a particular software build that includes compile-time or run-time behavioral changes in the firmware. They may also introduce new features without compromising the present product’s operation.
Advantages of Firmware
Firmware is essential for home appliances, network hardware, and most electronic devices to work. Manufacturers provide firmware updates to users to enable devices to continue running efficiently and securely. Users can access firmware updates via the manufacturer’s website for download. The following are advantages of firmware:
1. Save costs
Nowadays, manufacturers often release improved consumer products such as television sets and computers to keep up with their competitors and improve their products’ quality. It is not rare to see manufacturers develop next-generation models of televisions or PCs after launching one. Upgraded models can feature bug fixes and improved resolutions to enhance user experience.
With firmware upgrades, users do not have to bear the cost of buying new products to access these new features. Users can download and install these firmware updates from the manufacturer’s website to access the new features. Thus, leading to reduced costs of buying new products with every new release.
Additionally, users can save on repair and maintenance costs. While manufacturers do their best to ensure that they make standardized products for their users, the products can develop bugs after the units are shipped. In such instances, manufacturers provide regular firmware updates to minimize the need for expensive bug fixes. Firmware updates can also reduce the need for device repairs or upgrades. For example, firmware updates that promote extended battery life can enable users to save on upgrading their batteries.
2. Boost performance
Firmware updates can lead to improved performances of various devices. The firmware sends instructions to devices to allow them to function as intended. During firmware updates, the firmware is optimized to perform better, which in turn helps the device’s processor to fine-tune its performance, improve consistency and enhance user experience.
For example, printers with updated firmware experience increased print resolution, faster execution times, and boot times. Televisions with updated firmware experience better resolution and fewer glitches.
Additionally, one can update the firmware to provide fixes to issues that may arise from frequent software updates. Devices such as PCs and mobile phones can experience lagging and delays in recognizing peripheral devices due to periodic software upgrades. Firmware updates can fix such issues. They also ensure that all components, including peripheral devices, work in harmony, reducing delays and improving performances in PCs, mobile phones, and Internet of Things (IoT) devices.
3. Improve features and security
The firmware enables most devices to work efficiently. Through firmware upgrades, users can enjoy the latest features that manufacturers provide without upgrading the hardware. Devices such as music players get updates to enable them to play additional files. Televisions with updated firmware experience better resolution that enhances user experience.
Firmware updates provide devices with additional operational instructions to improve performance and minimize security vulnerabilities. The hardware of PCs may put them at risk for security hacks. The firmware can be upgraded to mitigate such vulnerabilities present in their hardware, thus promoting security best practices. For instance, in May 2021, Dell released a replacement firmware update that fixed vulnerabilities in its hardware.
Top Best Practices for Using Firmware in 2022
When working with firmware, one must consider several key areas: development, security, updates, and downtime minimization. Let us look at the best practices to remember in each of these areas:
1. Firmware development best practices
The firmware enables devices to perform essential functions. When developing firmware, engineers should consider developing products that are reliable and can function as expected. To maintain the integrity of the firmware, a system’s root of trust (RoT) must be established and maintained, firmware images are signed and verified, and attestation of a secure boot. The top firmware development best practices are:
- Designers should first make a model system. This ensures that aspects of the device’s logging schema, data transfer model, and operational states are considered.
- Security should be designed from the early phases of firmware inception. Designers should conduct a threat model assessment on all system components as changes are made to establish trust boundaries and minimize potential exploits.
- Developers should use memory-safe practices such as initializing all variables, using safe strings and buffer functions and performing integer overflows and underflows checks. Additionally, they should use memory-safe languages.
- Developers should establish a robust source control system capable of enforcing policies such as code reviews before check-ins and triggering automatic testing hooks while generating testing reports.
- Before update releases, a security review of the firmware source code should be routinely reviewed. Organizations are also encouraged to invite external experts to check their code to get a fresh perspective. This will enable the organizations to eliminate any security issues they may have missed due to assumptions.
2. Firmware security best practices
In 2015, one of the most prominent cyberattacks happened when the Equation Group placed spyware in the firmware of victims’ hard drives. A lack of proactiveness in monitoring and performing regular updates on firmware is a significant factor that contributes to the increased appetite by hackers to target it. The top firmware security best practices are:
- Users should only install regular firmware updates from official and trusted sources to avoid installing malicious applications or malware on their devices. It is also possible to implement cryptographically signed pictures that enable the bootloader to validate the update’s authenticity. With hardware security components, one should save sensitive data like private keys and password credentials in memory. Similarly, they can be encrypted using cryptographic algorithms.
- Before releasing any firmware, one must delete any extraneous pre-production build code to prevent the introduction of back doors.
- All input and output information should be verified and encrypted to prevent accidental system execution and attacks through the insertion of malicious programs that might compel the device to run.
- Transit data should be encrypted using industry-standard encryption configurations for transport layer security (TLS) to ensure that it remains private and untampered.
3. Firmware update best practices
To ensure a smooth running of operations, it is essential for users to not only keep their operating systems and applications updated but also update their firmware. Firmware upgrade policies are integrated into standard data center procedures to ensure regular updates are made. Manufacturers must provide their users with secure access to firmware updates to avoid introducing malicious codes into their devices. The top firmware update best practices are:
- One should establish cooperation between different members in an organization before any firmware update is performed. This will ensure those update decisions are arrived at in a coordinated manner and that minimal interruptions occur during updates.
- Users are advised to read the release notes to learn more about fixed issues and new features introduced.
- As part of the disaster recovery plan, a full backup of the old configurations should be made to enable users to get their devices running in case the upgrade fails.
- A backup of the old firmware should also be made available.
- Users should double-check that their systems are working and are well prepared for emergencies before committing any firmware updates.
4. Best practices to minimize firmware downtime
The process of firmware maintenance is a common pain point for most users. Users complain of experiencing downtimes that lead to interrupted work schedules and decreased productivity. As a result, some of them prefer to skip firmware maintenance schedules leading them to fall behind. These users often expose themselves to issues already fixed in later service packs or releases. The best practices to minimize firmware downtime are:
- When a new service pack is released, users are advised to review the service pack fix list README to see if any critical fixes apply to their environments or configurations. If it includes a high-impact/pervasive (HIPER) fix that applies to them, they should install the service pack as soon as a maintenance window is available.
- It is acceptable for a “differed fix” to remain pending until the subsequent scheduled reboot.
- Users need to be on a release level supported with service packs.
- It is recommended that users plan to perform firmware maintenance at least twice a year.
- Users can use their current firmware version if they don’t require the features provided by the new release as long as their version is supported.
Firmware is a crucial part of any hardware device, especially electronics designed for consumers or business users. These devices have a degree of black-boxing, which means that users cannot dive into their core workings and obtain root control legitimately. It is the firmware’s responsibility to keep the hardware up and running, secure, and usable, which is why DevOps engineers spend much of their time on firmware design and updates. Regular firmware releases help maintain performance and increase the shelf-life of devices for several years.
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