FreeBSD/sparc64 is a work in progress.

If you are interested in running FreeBSD on sparc64 hardware, please
join the freebsd-sparc@FreeBSD.org mailing list by sending a message
to majordomo@FreeBSD.org with 'subscribe freebsd-sparc' in the body
of the message.

The files necessary to install FreeBSD/sparc64 are located in the
/pub/FreeBSD/development/sparc64 directory.