multiboot header error

[Constantine Kousoulos]

After successfully installing GRUB2 from cvs (thanks Jerone!), i 
decided to further test it on my amd64 machine.

At first, i built the sample kernel from 
http://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Example-OS-code 
using the '-m32' gcc flag and by marking boot.S with the '.code32' 
directive. All these effectively created an elf32 image on my 
amd64 machine which built and booted without any trouble. :)

Then i proceeded to check if i can make GRUB2 boot the same kernel 
as a native elf64 image. So, i removed the above mentioned flag 
and directive, renamed any 'pushl' instruction to 'pushq', renamed 
registers 'eax' to 'rex' and 'ebx' to 'rbx', modified the magic 
number (0xe85250d6) and alingned it to 64-bits. When i tried to 
boot it i got: "error: No multiboot header found". :(

Is there something i did or didn't do correctly? I would greatly 
appreciate any feedback!

Thanks,
Constantine