Like many others, I have had OS 10.11 working well on my Mac Pro 1.1 and installed an update from 10.11.5 to 10.11.6...was using a "non supported" Gefore 740 graphics card and would just boot to black screen...put in "officially working" ATI card, would do the same thing...used time machine to roll back but now get this Kernel error. I have read and read and read and read but am not a coder and am having problems getting this working again. I understand that there is a driver missing and it seems that just reloading the old boot.efi would do the trick...connected to my MacBook pro, ran in target mode and tried replacing to no avail... Does anyone have a simple way of fixing this? Thank You.