The leptonic CP violation phase $\delta_{CP}$ and the neutrino
mass-ordering are two current unknowns in neutrino oscillation physics. We have shown earlier that the value of $\delta_{CP}$ can be estimated, ``irrespective" of the neutrino mass-ordering, using sub-GeV atmospheric neutrinos. This enables the possibility of studying the effects of other oscilliation parameters on $\delta_{CP}$. Here we perform a study of the effect of the 1-2 oscillation parameters $\theta_{12}$ and $\Delta{m^2_{21}}$ on the $\delta_{CP}$ sensitivity.