We recently presented a theory of bistability in a nonlinear distributed-feedback (DFB) structure,1 in that work the coupling between forward and backward propagating waves was provided solely by Bragg-scattering from a periodic index perturbation built into the otherwise homogeneous medium. With the recent demonstration of bistability in the high-index semiconductors GaAs2 and InSb,3 it is clear that the external feedback due to Fresnel reflections will play a major role in any practical DFB bistable optical device. These end reflections have already been considered in the case of semiconductor DFB lasers.4 In this paper we show that even minor end reflections can drastically alter the switching threshold of DFB bistable optical devices.