Yocto

Many embedded Linux projects start by assembling a system by hand: download a cross compiler, build the kernel, copy BusyBox, add libraries, package rootfs, and drop in the application.

That may boot a board, but it quickly breaks down in a product:

• which cross toolchain built this image
• which kernel config and device tree were used
• where each library in rootfs came from
• why the same application links differently on another machine
• whether production images, debug images, and SDKs can be generated from one configuration
• whether the same system can be rebuilt six months later

Buildroot and Yocto do not mainly solve “how to install a few packages”. They solve this: how to put the toolchain, bootloader, kernel, rootfs, packages, image, and SDK into a repeatable build system.