  Recent cosmic-ray measurements are challenging our models of propagation in
the Galaxy. A good characterization of the secondary cosmic rays (B, Be, Li and
sub-iron species) is crucial to constrain these models and exploit the
precision of modern CR experiments. In this work, a Markov chain Monte Carlo
analysis has been implemented to fit the experimental flux ratios between B, Be
and Li and their flux ratios to the primary nuclei C and O. We have fitted the
data using two different parametrizations for the spallation cross sections.
The uncertainties in the evaluation of the spectra of these secondary cosmic
rays, due to spallation cross sections, have been considered by introducing
scale factors as nuisance parameters. We have also tested two different
formulations for the diffusion coefficient, which differ in the origin of the
high energy hardening of cosmic rays. Additionally, two different approaches
are used to scale the cross sections, one based on a combined analysis of all
the species ("combined" analysis) and the other reproducing the high energy
spectra of the secondary-to-secondary flux ratios of Be/B, Li/B, Li/Be
("scaled" analysis). This allows us to make a better comparison between the
propagation parameters inferred from the cross sections parametrizations tested
in this work. This novel analysis has been successfully implemented using the
numerical code DRAGON2 to reproduce the cosmic-ray nuclei data up to $Z=14$
from the AMS-02 experiment. It is found that the ratios of Li favor a harder
spectral index of the diffusion coefficient, but compatible with the other
ratios inside the observed $2\sigma$ uncertainties. In addition, it is shown
that, including these scale factors, the secondary-to-primary flux ratios can
be simultaneously reproduced.
