sparc64 network autoconfiguration

[Andrei Borzenkov]

Documentation says

On sparc64 GRUB is unable to determine which server it was booted from.

Could someone clarify what it means here? sparc64 is ieee1275 that
supports auto configuration for network boot - at least, it has code
to do it. So far the only platform where it is not possible seems to
be uboot (which is also missing from Platform limitations section).