We have previously reported on chemical abundance trends with evolutionary state in the globular cluster NGC 6397 discovered in analyses of spectra taken with FLAMES at the VLT .
Here , we reinvestigate the FLAMES-UVES sample of 18 stars , ranging from just above the turnoff point ( TOP ) to the red giant branch below the bump .
Inspired by new calibrations of the infrared flux method , we adopt a set of hotter temperature scales .
Chemical abundances are determined for six elements ( Li , Mg , Ca , Ti , Cr , and Fe ) .
Signatures of cluster-internal pollution are identified and corrected for in the analysis of Mg .

On the modified temperature scales , evolutionary trends in the abundances of Mg and Fe are found to be significant at the 2 \sigma and 3 \sigma levels , respectively .
The detailed evolution of abundances for all six elements agrees with theoretical isochrones , calculated with effects of atomic diffusion and a weak to moderately strong efficiency of turbulent mixing .
The age of these models is compatible with the external determination from the white dwarf cooling sequence .
We find that the abundance analysis can not be reconciled with the strong turbulent-mixing efficiency inferred elsewhere for halo field stars .
A weak mixing efficiency reproduces observations best , indicating a diffusion-corrected primordial lithium abundance of \log \varepsilon ( { Li } ) = 2.57 \pm 0.10 .
At 1.2 \sigma , this value agrees well with WMAP-calibrated Big-Bang nucleosynthesis predictions .