Here is Xperia Go JB based custom boot image optimised for Xperia U, contain Xperia U CWM Touch and modified ramdisk from Xperia Go JB, allso contain custom JB kernel and kernel modules compiled for Xperia U -> http://d-h.st/bHB Enjoy!

Disclaimer:
I am not responsible for anything and you are doing/testing/installing...etc this on your own risk!!! If you no want to use this simple skip this!