It's in it's own thread here in the dev forum.
I just tried every version of fastboot I could find to flash the system.img and it's just to large.
@TheJesus I think it may be a good idea to edit the OP and remove the system.img. People looking to go back to stock can flash the zip I provided
HERE
I didn't add the recovery.img to the zip although I could. That way all you'd have to do is flash the zip in recovery and your device would be 100% stock. Eliminate the need to fastboot the recovery.img afterward...