After updating an EFI booting Mac to 3.7.4-204, I get a brief message from GRUB saying that the kernel must be loaded first, then a kernel panic. The new menu entry for this kernel uses linuxefi, but it uses initrd not initrdefi as the other entries do.
If I manually edit the grub.cfg to use initrdefi, I don't get this error or panic. And grub2-mkconfig also produces a grub.cfg using initrdefi. Therefore it appears the lack of this command causes boot failure, but I'd like to know what component the bug should be filed against.