Modified M–R relations for accreting nonmagnetized and magnetized 0.45 M_⊙ HeCO WDs and 1.02 M_⊙ CO WDs. In all magnetized cases, η = 1.1, γ = 0.8 (η and γ describe the magnetic field profile defined in Appendix A). The end of each track denotes the maximum mass of a stable WD created. In the HeCO cases, the triggering of unstable helium burning leads to the WD being destabilized before the mass limit is reached. We confirm this effect more clearly by comparing the cases between nuclear reactions enabled in the code (“reactions on”) and the cases when nuclear energy release does not go into the stellar structure equations (“reactions off”). Core carbon ignition in the CO WDs occurs close to the maximum mass.