[Senko]

Hmm I read that differently as in if your race is not a 0 HD race then you must choose a 0 HD race from the core rulebook. The first half of the sentence only specifies the Eidolon will match your race then the second half clarifies if you aren't a 0 HD race you must choose one from the core rule book.

I can see where your coming from though as you could read that as assuming your core race is going to be from there and you wouldn't be able to choose a Aasamir (GM generosity aside) instead of say a troll. Still either way the choices need to be adjusted. If my readings correct you should be able to choose Aasamir, Tieflings and the like because they are 0 HD races. If your reading is correct then all the races that aren't from the core rulebook (Wayang, Drow Noble, Duregar Tyrant, etc) which are currently selectable need to be removed as options.

Personally I'd prefer to go with my reading just for more options over less and while an Aasamir could easily summon a human ancestor it'd be odd for say a Kitsune or Goblin to use one of those races as an ancestor but not my call in the end.