What build I should choose?

well, i just tried using MLO, u-boot and uImage at http://downloads.angstrom-distribution.org/demo/beagleboard/

and configured kernel by using Robert Nelson’s script https://github.com/RobertCNelson/linux-dev

Thanks Robert for his nice work and saving us so much time… So far it works well. I can compile the kernel and change the image. I know this sounds very newbie, but I have been struggling with this for weeks and it Feels great!