# Building a small Raspberry Pi System from Scratch

What you are looking at right now is a collection of instructions on how to
bootstrap a tiny system for a Raspberry Pi 3 board.

We will bootstrap the system by building our own cross compiler toolchain
and then using it to cross compile everything we need for a working Linux
based OS.

In contrast to similar guides, I try to explain why we are doing the things
the way we are doing them, instead of just throwing a bunch of copy-paste
command lines around (I'm looking at you, LFS).

This guide is divided into the following parts:

* [Building a cross compiler toolchain](crosscc.md).
* Cross compiling a statically linked BusyBox and the kernel. The kernel has
  a built-in initrd containing our BusyBox. We will make it boot on the
  Rapsberry Pi and explore some parts of the Linux boot process.
* Building a more sophisticated userland. The userland will be packed into a
  SquashFS image. The BusyBox based initrd is modified to mount it and switch
  into it.