I've updated to the latest firmware on my ATV2 and the latest seas0npass and latest atv flash (black)
and now there is no xbmc-install under "manage extras".
why is that? have you removed xbmc so we can't install it thru atv flash anymore?
edit: nevermind, found the answer to this myself, xbmc isn't supported yet (at least not officially and only if manually installing with ssh, but dropbox-link dead)