you can try to load the extra.lzma first if this is working for the i210.
initrd $img/ramdisk.lzma $img/$extra_initrd
initrd $img/$extra_initrd $img/ramdisk.lzma
I just want to say that this worked for me.
I am runnung an esxi server with an i210 passed through.
For people who do not understand this completely: you have to do the change in grub.cfg. How to edit this file is described here (Point 5):
I also want to state, that my LSI3008 controller is working. A bare metal setup on the X11SSL-CF board should work as well.