  In this paper we consider the Balmu\c{s}-Montaldo-Oniciuc's conjecture in the
case of hemispheres. We prove that a compact non-minimal biharmonic
hypersurface in a hemisphere of $S^{n+1}$ must be the small hypersphere
$S^{n}\left(1/\sqrt{2}\right)$, provided that $n^{2}-H^{2}$ does not change
sign.
