What are embedded Linux distributions?
Embedded Linux distributions are customized versions of the Linux kernel, along with related tools and applications – called packages. They are designed specifically for embedded systems, fitting their unique requirements, such as limited resources, high reliability, and strong security needs.
Embedded Linux distributions are designed to work closely with the hardware, they rely on the Board Support Package (BSP) of the system (provided by the SOM maker / Silicon vendor), a critical component of embedded Linux which provides the essential interface that enables the hardware to communicate smoothly with the operating system (OS).
Note that embedded Linux distros include all available software packages for the system, while the Linux image is a slimmed-down version that contains only the necessary components for your system. This selective approach ensures that the embedded system runs efficiently on the limited resources typical of embedded devices.
Nowadays, embedded Linux powers a wide range of devices, from medical devices to wearables and industrial machinery.
What should you expect from Linux distributions for embedded systems?
When building or choosing embedded Linux distributions, several factors should be taken into account:
Hardware integration: The distribution must be tightly aligned with your hardware’s capabilities, optimizing for factors like processing power, memory, and storage.
Customization and performance: Efficiency is critical in embedded systems. The distribution should be lightweight, including only the software components needed to run the system effectively.
Security: Security plays a vital role in embedded systems, especially when these devices operate in remote or sensitive environments. Important security features to consider include secure boot, secret management, LTS support…
Firmware updates: Embedded devices often require remote firmware updates since users are typically not present when the updates occur. A reliable and resilient OTA update mechanism is crucial to ensure the system remains stable and secure over time.
Development and production environments: The development environment should be open and easily accessible to developers, while the production environment needs to be more restricted to safeguard against unauthorized access. This will give you distinct development and production images.
Now let’s focus on the main distinctions between off-the-shelf and custom Linux distros:
Strengths and weaknesses of standard, off-the-shelf embedded Linux distributions
Ubuntu Core and Debian are the most classical standard embedded Linux distributions we can find in the
embedded world.
These distributions offer a sense of familiarity by aligning with typical Linux usage patterns, making them particularly appealing to users accustomed to the desktop environment. The strength of Linux distros like Ubuntu Core and Debian lies in their expansive ecosystems, featuring wide repositories and precompiled packages that facilitate the seamless integration of features into embedded systems. Users also benefit from regular updates, ensuring a secure and up-to-date operating environment, making these distributions a reliable foundation for those prioritizing ease of use, stability, and a well-supported software ecosystem.
However, despite their strengths, off-the-shelf Linux distributions like Ubuntu Core and Debian face notable limitations in the context of embedded systems. These drawbacks become evident, especially when implementing advanced security features such as secure boot, where the package manager’s inability to facilitate seamless updates poses a challenge. Additionally, these distributions often result in larger image sizes and limited customization options. Consequently, for embedded devices requiring high adaptability and intricate security measures, off-the-shelf Linux distributions may not fully meet your specific demands, and you should rather look at building your own tailor-made Linux distribution.
Consult our comparison of off-the-shelf Linux distributions.
Pros
✓ A standard way of working that resembles your Linux usage, making it familiar on the desktop world
✓ Large ecosystem: These distributions have extensive repositories and precompiled packages, making it easier to manage expected features in the system
✓ Regular updates are provided from a patch & vulnerability point of view
Cons
⨉ The package distribution system is not adapted to the embedded world. If you are using Secure Boot, you cannot use the package manager to get updates
⨉ Image sizes are usually larger, and the level of customization is limited.
⨉ Not as flexible as needed for an embedded device. For example, the implementation of advanced security features like secure boot is not easy.
Strengths and weaknesses of custom embedded Linux distributions
A reliable build system is the foundation of embedded Linux development, providing a structured
environment for configuring, building, and customizing your embedded Linux image. The Yocto Project and Buildroot are two prominent build systems that streamline the development process.
- The Yocto Project offers extensive customization options and supports a wide range of hardware architectures. Simplifies the creation of custom Linux distributions, allowing OEMs to fine-tune every aspect of their system. Its layer-based approach and wide community make it a valuable tool for complex embedded projects.
- Buildroot is known for its simplicity and ease of use. A great choice for smaller projects or
when you need a minimal, fast-booting system. Lightweight, making it ideal for resource constrained embedded devices. However, Buildroot seems to be less and less supported by Silicon vendors and SOM makers.
Embarking on the creation of a custom embedded Linux distribution using tools like Yocto or Buildroot provides the capability to achieve meticulous customization of system images tailored to specific project requirements. This flexibility empowers the development of lightweight and optimized embedded systems, ensuring that the resulting distribution precisely aligns with the unique demands of the project. Furthermore, these tools simplify the integration process across diverse hardware platforms, streamlining the deployment of the custom Linux distribution on multiple devices.
A key strength lies in the centralized management of system configuration through recipes and layers, enhancing version control and reproducibility. This systematic approach enables firmware developers to track and replicate configurations, contributing to a stable and controlled development environment. Additionally, the automation of the build process enhances overall efficiency in development and maintenance. By automating compilation and configuration tasks, developers can save time and resources, facilitating a more streamlined and agile development workflow. Opting for tools like Yocto or Buildroot empowers developers to create highly customized, efficient, and well-controlled Linux distributions tailored precisely to the needs of embedded projects.
Despite these strengths, it’s essential to acknowledge certain weaknesses. The steep learning curve associated with these tools, attributed to their complexity, may pose a challenge for newcomers and require a significant investment of time and effort for proficiency. Additionally, the build time involved in generating an image through source-based compilation can be time-consuming, potentially affecting rapid development cycles.
Pros
✓ Allows fine-grained customization of system images based on specific project requirements, enabling the creation of lightweight and optimized embedded systems
✓ Eases integration on multiple hardware
✓ System configuration is centrally managed using recipes and layers, facilitating version control and reproducibility
✓ Automates the build process, making development and maintenance more efficient
Cons
⨉ Learning curve: These tools can have a steep learning curve due to their complexity. Users need to understand concepts such as recipes, layers, and bitbake to effectively create images
⨉ Build time: generating an image may take time due to source-based compilation, which can be a drawback for rapid development
Welma, a Linux distro at the frontier of off-the-shelf & custom solutions
Recognizing the benefits and drawbacks is crucial when considering custom embedded Linux distributions. To address these challenges, we’ve designed Welma Yocto Linux, a distribution at the frontier of off-the-shelf and custom solutions. Welma Yocto Linux offers the flexibility needed for customization while providing a ready-for-production Linux distribution based on Yocto, ensuring a balance between flexibility and convenience to precisely fit your system requirements.
Mastering embedded Linux in 2025
A comprehensive guide on embedded Linux systems development and maintenance
