This paper introduces CMOS/magnetic tunnel junction (MTJ)-based asynchronous single-track circuits for re-initialization free computing against power failures. In energy-harvesting applications, data processed might be lost due to frequent power failures, which usually requires the initialization phase after the power supply is recovered. To prevent the re-initialization for energy-efficient computing, the proposed single-track circuits are designed using MTJ devices as nonvolatile storage elements. As MTJ devices store data without power supply, data processed are immediately backed up to MTJ devices and are restored when necessary in order to continue operations. For safe restore operations, the proposed circuits eliminate metastable states that might occur in the backup phase. To evaluate the performance overheads due to the nonvolatile operations, the proposed single-track circuits are designed using 65nm CMOS/MTJ technologies and are compared with conventional volatile single-track circuits in several benchmarks.