  Strong coupling lattice QCD in the dual representation allows to study the
full $\mu$-$T$ phase diagram, due to the mildness of the finite density sign
problem. Such simulations have been performed in the chiral limit, both at
finite $N_t$ and in the continuous time limit. Here we extend the phase diagram
to finite quark masses, with an emphasis on the low temperature first order
transition. We present our results on the quark mass dependence of the critical
end point and the first order line obtained by Monte Carlo via the worm
algorithm.
