  We explore possible depletion factors for Li6 in the three stars where it has
been detected. To this end, we assume that 6Li/H scales as 16O/H throughout the
galactic evolution, an assumption motivated by the observations of a similar
scaling for 9Be. We examine the uncertainties attached to this modeling of 6Li
galactic evolution; we also incorporate a recent evaluation of the primordial
production of 6Li. The depletion factor D6, for 6Li, in HD84937, is constrained
to be less than 4 at 95% c.l.. This depletion factor is an extreme upper limit
on the depletion factor for 7Li. We conclude that the primordial abundance of
7Li cannot be higher that twice the observed value, since no current stellar
model is able to reproduce the observed trends of 7Li with temperature and
metallicity, and yet deplete 7Li by more than a factor 2, while satisfying
D6<4. All three 6Li observations are in excellent agreement with all standard
expectations: Big-Bang nucleosynthesis with 2<$\eta_{10}$<6.5, and standard
isochrones of 6Li survival. We discuss possible deviations from our assumption
of 6Li/H scaling with 16O/H, due to alpha-alpha creation of 6Li in various
sites. We notably reject stellar flares as a significant source of 6Li in
HD84937.
