Did you try this method ?
http://www.hackint0sh.org/forum/showthread.php?t=33566

I think iphone dev team gonna fix this problem soon...


Most of us got error message like this
AppleMRVL868z: Invalid calibration data in device tree


I read something. It is related to device tree..
"After booting up, we patch out signature check from AppleImage2NorAccess extention and proceed with flashing our custom firmware files (iBoot, LLB, DeviceTree, and pictures)"

iBoot is the last and most complicated bootloader on the devices, and is what actually loads up the kernel with device tree.

From : http://iphone-dev.org/s5l8900 : pwnage