How to access and modify the kernel sources in OpenEmbedded?

Good morning,

I am trying to use the OpenEmbedded framework in order to develop an application for colibri-T20.

I followed the instructions given by:

http://developer.toradex.com/knowledge-base/board-support-package/openembedded-(core)

I successfully configured and installed OpenEmbedded with LinuxImageV2.6.1. I also built the angstrom-lxde-image image without any problem.

Now, I would like to modify the Linux kernel sources and build the kernel. But I cannot find any source file in my local machine. Am I missing something? What is the correct procedure to access the kernel and U-boot source files?

Thanks for your attention,

Alberto Lessio

Information on compiling u-boot and linux kernel can be found here:
http://developer.toradex.com/knowledge-base/build-u-boot-and-linux-kernel-from-source-code