MacPro 1,1 boot 64-bit kernel from 32-bit UEFI

grub.conf

set default=0
set timeout=1

# insmod efi_uga
insmod all_video
insmod font

if loadfont ${prefix}/unicode.pf2
then
    insmod gfxterm
    set gfxmode=auto
    set gfxpayload=keep
    terminal_output gfxterm
fi

menuentry 'Arch Linux' {
	insmod gzio
  echo	'Loading Linux linux ...'
  # add_efi_memmap might do nothing, still need to test
	linux	/vmlinuz-linux root=rpool/ROOT/arch rw noefi add_efi_memmap nomodeset
	echo	'Loading initial ramdisk ...'
	initrd  /initramfs-linux.img
	echo	'booting ...'
	boot
}

menuentry "System restart" {
    echo "System rebooting..."
    reboot
}

menuentry "System shutdown" {
    echo "System shutting down..."
    halt
}