Encrypt Root Partition for beaglebone black

hi, I am using beaglebone black with debian (http://eewiki.net/display/linuxonarm/BeagleBone+Black)

I want to Encrypt root partition. I am reading bellow link…
http://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/
but as mention there…
How bootloader load new initramfs into memory…???
kindly help on this… what changes needed in uEnv.txt??
thanks in advance…

regards.