  We investigate the $g_2$-invariant bulk (1+1D, factorized) $S$-matrix
constructed by Ogievetsky, using the bootstrap on the three-point coupling of
the vector multiplet to constrain its CDD ambiguity. We then construct the
corresponding boundary $S$-matrix, demonstrating it to be consistent with
$Y(g_2,a_1\times a_1)$ symmetry.
