[U-Boot] confusion about running raw binary files

[apple pie]

Hi,
 
All along, I have been thinking is: to run an u-boot binary on a board,
two steps are required:
(1) configure u-boot
(2) cross-compile the source.
 
I was a bit confused when I was told the followings:
To run binary code, you do not need to create any specific images.
Just load the raw binary file to the right address, and start it at
it's entry point address using "go".
How could the code be run without first going through cross-compilation?
Could someone please help to clarify this?
 
Thanks,
 
Ivan