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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.

Core

Read firstAnatomy of an application-processor system
How an embedded Linux image is built, where board support lives, and how long kernels get fixes The Yocto Project or Buildroot compile a toolchain, kernel, bootloader and root filesystem from source. Board support merged into the main kernel keeps working as the kernel changes, while support only in a vendor's copy needs constant work to move forward. Long-term support kernels start with a projected two years of fixes, and in the October 2026 list run three to six years; the Civil Infrastructure Platform keeps selected kernels for ten years. Building a custom image Source code Yocto Project or Buildroot compiled from source Toolchain Kernel Bootloader Root filesystem Some products start from a Debian-based image instead. Where the board's hardware support lives Main kernel Vendor's copy of the kernel keeps working as the kernel changes constant work to move to newer kernels; less review How long a kernel gets fixes In recent years kernel.org has picked one LTS kernel a year LTS, projected at first two years, can be extended LTS, October 2026 list three to six years Civil Infrastructure Platform (CIP) ten years, selected kernels, for industrial use 0 2 4 6 8 10 years
Yocto Project or Buildroot build the system from source; support in the main kernel keeps working as it changes, and the kernel line you pick decides how long fixes last.

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.123
  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.53as of 6 October 2026
  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 · Yocto Project (Linux Foundation) · Project docs
  2. The Buildroot user manual · Buildroot · Project docs
  3. CIP: Linux kernel and core packages · Civil Infrastructure Platform (Linux Foundation) · Project docs
  4. A guide to the kernel development process: The importance of getting code into the mainline · kernel.org · Project docs
  5. Active kernel releases · kernel.org · Project docs
  6. Embedded Linux boot time optimization (training slides, updated 2026) · Bootlin · Reference