[U-Boot] U-boot porting experiment -- which board or CPU will be good for doing it first time

Hi,

I have been reading u-boot documentation for last few weeks.

I am looking forward to configure & write my own u-boot for some board or CPU . I will be doing it first time.

Please suggest some existing board for which we have opensource U-boot software available, which are good for someone to start ? I can study that & apply same concept to other Processors or boards. I will like to be an expert in u-boot porting.

TI sitara controllers or RPi(I have an Rpi) or some thing else ?

Please suggest something.

Regards, Allan