install refit to AppleTV
You could proberly boot it by installing refit to the AppleTV OS
(take a isntalled version from a mac, copy it via scp and enable it via the enable-always script)
USB keyboard should work on refit. Will let us access EFI shell which has some very serious advantages in booting :)
Someone wants to give it a try? I can't currently. Report back if working :) sadly I cannot test these nice ideas myself atm :(
Did anybody try to install refit already? I'd like to know if it's working. Would be greate to choose between my osx (on usb drive) and ATV install on startup.
Any EFI bootloader besides Apples "boot.efi" will not get loaded by EFI firmware. "boot.efi" is signed and EFI firmware checks the certificate before loading. And you're not going to brute force break the signing. It would take a long time (years).