Context : The secondary-to-primary B/C ratio is widely used to study Galactic cosmic-ray propagation processes .
The ^ { 2 } H/ ^ { 4 } He and ^ { 3 } He/ ^ { 4 } He ratios probe a different Z / A regime , therefore testing the ‘ universality ’ of propagation .

Aims : We revisit the constraints on diffusion-model parameters set by the quartet ( ^ { 1 } H , ^ { 2 } H , ^ { 3 } He , ^ { 4 } He ) , using the most recent data as well as updated formulae for the inelastic and production cross-sections .

Methods : The analysis relies on the USINE propagation package and a Markov Chain Monte Carlo technique to estimate the probability density functions of the parameters .
Simulated data are also used to validate analysis strategies .

Results : The fragmentation of CNO cosmic rays ( resp .
NeMgSiFe ) on the ISM during their propagation contributes to 20 % ( resp .
20 % ) of the ^ { 2 } H and 15 % ( resp .
10 % ) of the ^ { 3 } He flux at high energy .
The C to Fe elements are also responsible for up to 10 % of the ^ { 4 } He flux measured at 1 GeV/n .
The analysis of ^ { 3 } He/ ^ { 4 } He ( and to a less extent ^ { 2 } H/ ^ { 4 } He ) data shows that the transport parameters are consistent with those from the B/C analysis : the diffusion model with \delta \sim 0.7 ( diffusion slope ) , V _ { c } \sim 20 km s ^ { -1 } ( galactic wind ) , V _ { a } \sim 40 km s ^ { -1 } ( reacceleration ) is favoured , but the combination \delta \sim 0.2 , V _ { c } \sim 0 , and V _ { a } \sim 80 km s ^ { -1 } is a close second .
The confidence intervals on the parameters show that the constraints set by the quartet data are competitive with those brought by the B/C data .
These constraints are tighter when adding the ^ { 3 } He ( or ^ { 2 } H ) flux measurements , and the tightest when further adding the He flux .
For the latter , the analysis of simulated and real data show an increased sensitivity to biases .
Using secondary-to-primary ratio along with a loose prior on the source parameters is recommended to get the most robust constraints on the transport parameters .

Conclusions : Light nuclei should be systematically considered in the analysis of transport parameters .
They bring independent constraints which are competitive with those obtained from the B/C analysis .