  The presence of convective motions in the atmospheres of metal-poor halo
stars leads to systematic asymmetries of the emergent spectral line profiles.
Since such line asymmetries are very small, they can be safely ignored for
standard spectroscopic abundance analysis. However, when it comes to the
determination of the 6Li/7Li isotopic ratio, q(Li)=n(6Li)/n(7Li), the intrinsic
asymmetry of the 7Li line must be taken into account, because its signature is
essentially indistinguishable from the presence of a weak 6Li blend in the red
wing of the 7Li line. In this contribution we quantity the error of the
inferred 6Li/7Li isotopic ratio that arises if the convective line asymmetry is
ignored in the fitting of the lithium blend at 6707 A. Our conclusion is that
6Li/7Li ratios derived by Asplund et al. (2006), using symmetric line profiles,
must be reduced by typically dq(Li) ~ 0.015. This diminishes the number of
certain 6Li detections from 9 to 4 stars or less, casting some doubt on the
existence of a 6Li plateau.
