Thanks for the many tips. I will test it with removing the drivers first, I have read that they are problematic, but not during the power off. If this works i'll try it with 'Xenial next' kernel.
@tkaiser
Or do you mean the whole image? Are the wifi modules only in the image?
@Igor
Is the Mali 400MP2 GPU not supported in the modern kernels? Or why do i lose "video acceleration functions"? Will it be later implemented?