A complete non-homentropic boundary resolution method for a flow upstream and downstream an intra-pipe restriction is considered in this article. The method is capable of introducing more predictable quasi-steady restriction models into the boundary problem resolution without adding artificial discharge coefficients. The traditional hypothesis of isentropic contraction, typically considered for the boundary resolution, is replaced by an entropy corrected method of characteristics (MOC) in order to be consistent with a non-homentropic formulation. The boundary resolution method is designed independently of the quasi-steady restriction models which allows obtaining a greater modeling flexibility when compared with traditional methods. An experimental validation at unsteady conditions is presented using different restriction quasi-steady models to illustrate the effectiveness of the proposed boundary resolution method in terms of predictability as well as flexibility.