@p3c0 There may be some advanced method for doing this.
But They have given sample-root-file-system and kernel source. This file system contains full ubuntu 14.04. And provided documents to compile kernel and flashing this file system to TX1 eMMC.
I think mostly TX1 user use this board in Robotics, Machine learning and embedded visual computing applications. So they required full ubuntu.
As for now i don't know any method to do that nor any post related on their forum. I will post a question on there forum. And hope for their reply soon.