Cannot boot from dual bios/uefi boot CD

[John Frankish]

Hi,

I'm trying the create a dual bios/uefi boot iso to burn to CD/DVD and boot
both bios and uefi.

The bios boot works fine
On two different machines, the uefi boot gets to the grub menu list:

On a dell laptop choosing the grub menu item boots to the linux console
prompt, but will not accept any keyboard input
On a mac mini the boot hangs without error message after choosing the grub
menu item.

Note that in both cases, I can enter grub commands from the prompt and can
also edit the grub menu entries. In addition, both the bios and uefi boot
are using the same vmlinuz and initrd files. Finally a more standard uefi
installation to usb stick boots on both machines without problems.

I'd appreciate any help and/or suggestions as to why this doesn't work -
details below.

Regards
John

The iso was created as follows:

$ x86_64-grub-mkimage --format=x86_64-efi --output=BOOTX64.EFI
--prefix=/EFI/BOOT/grub --config=/tmp/grub.cfg acpi ahci all_video appleldr
at_keyboard bitmap_scale ata boot cat chain configfile cs5536 echo efi_gop
efi_uga ehci ext2 fat font gfxmenu gfxterm gzio halt help hfs hfsplus
iso9660 jpeg keylayouts linux loadbios loadenv ls minicmd normal ohci
part_gpt part_msdos png probe regexp reboot search search_fs_file
search_fs_uuid search_label test tga true udf ufs1 ufs2 uhci usb_keyboard
zfs.

Where /tmp/grub.cfg is:
search.fs_label CorePure64 root
set prefix=($root)/EFI/BOOT/grub

efiboot.img created as follows:

$ dd if=/dev/zero of=efiboot.img bs=1K count=1440
$ mkdosfs -F 12 efiboot.img
$ mkdir /tmp/image
$ sudo mount efiboot.img /tmp/image
$ sudo mkdir -p /tmp/image/EFI/BOOT
$ sudo cp BOOTX64.EFI /tmp/image/EFI/BOOT
$ sudo umount /tmp/image

And copied to the iso file structure as follows:

/EFI/BOOT/efiboot.img
/EFI/BOOT/grub/grub.cfg
/EFI/BOOT/grub/fonts/unicode.pf2

Where grub.cfg is:

loadfont unicode
set gfxmode=auto
insmod efi_gop
insmod efi_uga
insmod gfxterm
terminal_output gfxterm

menuentry "corepure64" {
  linux /boot/vmlinuz64 loglevel=3
  initrd /boot/corepure64.gz
}

And finally the iso is created as follows:

$ sudo mkisofs -pad -l -r -J -V CorePure64 -no-emul-boot -boot-load-size 4
-boot-info-table -b boot/isolinux/isolinux.bin -c boot/isolinux/boot.cat
-hide-rr-moved -eltorito-alt-boot -eltorito-platform efi -b
EFI/BOOT/efiboot.img -no-emul-boot -o CorePure64-6.0.iso /tmp/pkg