  We explore the interplay between the equivalence principle and a
generalization of the Heisenberg uncertainty relations known as extended
uncertainty principle, that comprises the effects of spacetime curvature at
large distances. Specifically, we observe that, when the modified uncertainty
relations hold, the weak formulation of the equivalence principle is violated,
since the inertial mass of quantum systems becomes position-dependent whilst
the gravitational mass is left untouched. To obtain the above result, spinor
and scalar fields are separately analyzed by considering the non-relativistic
limit of the Dirac and the Klein-Gordon equations in the presence of the
extended uncertainty principle. In both scenarios, it is found that the ratio
between the inertial and the gravitational mass is the same.
