Comment # 13 on bug 1092590 from Marcus Schaefer

This sounds like a parted problem to me. It probably has a problem and waits
for an answer. As I can't reproduce it we need to debug deeper. Can you do the
following:

Boot with:

    rd.debug rd.break=initqueue

This will stop inside of the initrd after the initqueue stage has passed.
You could also consider to use the serial console (console=ttyS0)

When you are at that stage call the following:

   parted -m -s /dev/mmcblk0 unit cyl print | grep -v Warning:

This is what the kiwi dracut code calls and is the call where you
encountered the hang and that should give you the reason why

Thanks