The answer to this question was immensely helpful to me and my new Vaio Z3. The issue that I am having now is that after replacing bootmgfw.efi with grubx64.efi and renaming, it boots directly to grub console. I dont even get a menu where i can chose ubuntu. I tried putting a grub.cfg file next to the new bootmgfw.efi(grubx64.efi), no go?
Any ideas how i can get the renamed grubx64.efi to find all the rest of the grub stuff outside of the ESP in my linux parition?
Or do i have to move all grub files to /EFI/Microsoft/Boot on ESP?