Booting OS in the Secure World and Normal World

Hello guys,

I am currently exploring the ARM TrustZone. I am working on a i.MX53 QSB and I want to run a Linux in the Secure World (I know that it is not the thing to do, but I just want to try) and another Linux in the Normal World. As I am new to the Linux Kernel and the TrustZone, I can't see how to do to boot two OS. Should I use U-boot to boot the first linux in the Secure World and then from the Secure World kernel boot the Normal World kernel ? Or is it U-Boot which boot the 2 kernels ?

Thank you