# Embedded Linux

Running Linux on a device usually means building or adapting your own small Linux system, and keeping it updated for as long as the product is in use.

Page: https://dharanova.com/learn/embedded-linux · Track: Run · Level: Core · Facts last checked 7 October 2026

Read first: [Anatomy of an application-processor system](https://dharanova.com/learn/anatomy-of-an-mpu-system.md)

Diagram: Top: source code goes into the Yocto Project or Buildroot, which compile a toolchain, kernel, bootloader and root filesystem; some products start from a Debian-based image instead. Middle: support in the main kernel keeps working as new kernels come out, while support in a vendor's copy needs constant work to move forward and gets less review. Bottom, a bar chart in years: an LTS kernel is first projected two years of fixes, which can be extended; kernels in the October 2026 list run three to six years; the Civil Infrastructure Platform keeps selected kernels for ten.

## Key points

1. Custom embedded Linux images are usually built with the Yocto Project or Buildroot, which compile a toolchain, kernel, bootloader and root filesystem from source; some products instead start from a Debian-based image. [1][2][3]
2. Hardware support that exists only in a chip vendor's own copy of the kernel needs constant work to move to newer kernels, and gets less review. Support merged into the main kernel keeps working as the kernel changes, so long-term updates are much easier. [4]
3. kernel.org picks some kernels for long-term support (LTS), in recent years one a year. Each usually starts with a projected two years of fixes, which can be extended; in the October 2026 list they run three to six years. The Civil Infrastructure Platform maintains selected kernels for ten years for industrial use. (as of 6 October 2026) [5][3]
4. Even a well-tuned embedded Linux system usually takes one to several seconds to boot, because it goes through a bootloader, the kernel and user-space start-up. Microcontroller firmware skips most of those steps, which matters for anything that must respond as soon as power returns. [6]

## Sources

1. [Yocto Project overview](https://www.yoctoproject.org/about/project-overview/), Yocto Project (Linux Foundation)
2. [The Buildroot user manual](https://buildroot.org/downloads/manual/manual.html), Buildroot
3. [CIP: Linux kernel and core packages](https://www.cip-project.org/about/linux-kernel-core-packages), Civil Infrastructure Platform (Linux Foundation)
4. [A guide to the kernel development process: The importance of getting code into the mainline](https://docs.kernel.org/process/1.Intro.html), kernel.org
5. [Active kernel releases](https://www.kernel.org/category/releases.html), kernel.org
6. [Embedded Linux boot time optimization (training slides, updated 2026)](https://bootlin.com/doc/training/boot-time/boot-time-slides.pdf), Bootlin