[yocto] Board files vs. device tree

[Fabian Schwartau]

Hi,

I am building a system with yocto for a board which is similar to 
Beagleboard-xM. So I used beagleboard as a starter. However, the kernel 
is not booting. Uboot just tells me that he is starting the kernel and 
then nothing happens any more.
So I guess there is something wrong with the pin muxing as my board is a 
little different from Beagleboard.
At the moment I am using the device tree file for beagleboard-xm by 
passing it with the uboot command
bootm ${loadaddr} - ${dtbaddr}
I looked around in the kernel and had to notice that there are still 
several board  files build in the kernel.
When there are several board files compiled into the kernel, how does 
the kernel determine the right one at boot time?
What does the kernel do if there are board files activated and I am also 
passing a device tree?
Why are there still board files when the specific board has already a 
device tree file?