This message was posted on behalf of Intel Corporation
Thanks for reaching out!
I'm sorry, I don't understand your question. What do you mean by extracting the BSP out of the build system?
If you'd like to have to build Aero's image using its BSP, I'd suggest you to follow the guide found in https://github.com/intel-aero/meta-intel-aero/wiki/Quickstart-Guide, it provides steps on how to do so.
I hope this information helps you,
If you are familiar with yocto, you can start by forking meta-intel-aero layers and configuring them to your preference: meta-intel-aero/layer.conf at cea218cf58878d02e71f6e53e07977d4ecf2d6d7 · intel-aero/meta-intel-aero · GitHub - remove the stuff you don't need.
If you just want to change the kernel version, feel free to use upstream yocto-embedded kernels - an example to this is from dev-branch where I started this process: kernel: yocto 4.4.41 instead of upstream 4.4.52 · intel-aero/meta-intel-aero@0cd3ca1 · GitHub
Or replace the kernel image under /boot with your own.
If you mean completely different OS (non-Linux kernel), the minimum requirement is that your OS installation media could boot from the BIOS and install itself. Like you would boot, for example, Ubuntu installation media.