  We present Li abundances for 73 stars in the metallicity range -3.5 < [Fe/H]
< -1.0 using improved IRFM temperatures (Casagrande et al. 2010) with precise
E(B-V) values obtained mostly from interstellar NaI D lines, and high-quality
equivalent widths (errors ~ 3%). At all metallicities we uncover a
fine-structure in the Li abundances of Spite plateau stars, which we trace to
Li depletion that depends on both metallicity and mass. Models including atomic
diffusion and turbulent mixing seem to reproduce the observed Li depletion
assuming a primordial Li abundance ALi = 2.64 dex (MARCS models) or 2.72
(Kurucz overshooting models), in good agreement with current predictions (ALi =
2.72) from standard BBN. We are currently expanding our sample to have a better
coverage of different evolutionary stages at the high and low metallicity ends,
in order to verify our findings.
