Talk about existing available support for using external pre-built binary toolchains in the Yocto Project. What is provided and how to use it. What are the limitations - uncover and explain ways of overcoming those. Overview examples of existing implementations for using toolchains from CodeSourcery and Linaro, as well as adding support for new toolchains, such as from the Arago Project.

Provide the guideline for rolling own pre-built binary toolchain from the Yocto Project and tips for making it usable inside of the Yocto for building filesystem images and SDKs. As well as what's missing and how to enable re-packaging it in the resulting SDK, that can be fed back into the Yocto Project again, completing the circle.

Delve into Canadian-cross, associated pros and cons - benefits of self-contained binaries, "relocatability" issues and mixing canadian with regular cross binaries.