Beagle Bone Black - uboot


I am working on Beagle Bone Black AM335x platform and started porting U-boot for the same.

I have followed steps for building U-boot, Kernel and rootfs on below mentioned link,

I am able to compile it successfully but when I try to load my kernel image using u-boot mentioned on this link is not able to load.

I have below quires on this git repo:

  1. Why this u-boot has been patched?
  2. How this rootfs is built?

Once I get my board up after loading images mentioned on this link i am trying to connect HDMI to LCD Monitor. It is taking 2mins to start and it is not quick though.
Could you please share which window manager is good to use as i can see there is a lot of difference when i boot with built images and one with default flashed image which has come beagle bone black board.

Kindly let me know your suggestions/ feedback.

Your suggestions are highly appreciated.