I had this _same_exact_ problem yesterday. And once again, Chris Murphy, you had the answer, so I thank you again.
As Mr. Murphy pointed out, the problem was caused by me having a hybrid GPT/MBR setup. Simply changing it back to pure GPT fixed the problem: sudo gdisk /dev/sda x //Enters the Expert menu n //Creates a new protective MBR w //Writes - actually does it Now I can chainload Apple's boot.efi file just fine without the error "not a valid root device". The long, long, complex menuentry generated by grub-mkconfig to boot Mac OS X still doesn't work. What's weird is that I used to be able to chainload boot.efi with a hybrid setup no problem. But after updating my Grub efi image (made from Grub compiled from source from bzr a couple days ago), I got the error. Why would it no longer be able to load the efi image off a hybrid disk? It makes no sense to me because it can still see and read the file (ls command) off one. Cheers, Jake _______________________________________________ Help-grub mailing list Help-grub@gnu.org https://lists.gnu.org/mailman/listinfo/help-grub
