$^{10}$B) are pure secondary species and that all the heavier elements contain a secondary and a primary component. We assume the primary injection to follow a universal power law in rigidity with index $\alpha$. The secondary component is computed by a full spallation network using the  cross-section parameterization (see appendices of [@GenoliniEtAl2018]). It has been shown in [@DeromeEtAl2019] that this parameterization provides the best agreement with the data, and that uncertainties on spallation cross sections are satisfactorily taken into account using only the $^{12}{\rm C}+{\rm H}\rightarrow {}^{11}{\rm B}$ production cross section as nuisance parameter with the “normalization, slope and shape” (NSS) strategy. For each run, the [*initial*]{} default procedure is to fix the normalization of the primary components of all elements to the 10.6 GeV/nuc data point of HEAO-3 [@Maurin2018], except for the CNO elements which affect more directly the B/C ratio: The latter ones are normalized to the C, N, O data of AMS-02 at a rigidity of 50 GV. The power-law index $\alpha$ is first set to 2.3, and fixed later via the iterative procedure explained below. The solar modulation of CRs is described in the force-field approximation, for which the Fisk potential $\phi_{\rm F}$ is averaged over 