Assuring functional correctness of smart mobility platforms is a critical task for enhancing reliability and safety. Hierarchical State Transition Matrix (HSTM) is a popular software design language, which can also be used for designing fundamental software of smart mobility platforms. For HSTM designs with complex hierarchical structure, it is often helpful if paths, which lead from the first-time value-change of a variable to subsequent references of the variable, can be easily understood by HSTM designers. In this paper, we describe an automatic tool called ZipPath, which can output such paths, including the shortest one, of an HSTM design. We examine the effectiveness of ZipPath with a running example. Although simple, ZipPath can be practically helpful for designers to develop correct HSTM designs.