Ultra-low-power microcontrollers have historically not offered MPUs; only recently have MPUs become more prevalent, but many lack the functionality for sufficient memory management and protection. Thus, those who develop multi-application, multi-tenant platforms isolate applications using compile-time or run-time software sandboxing (e.g., AmuletOS), imposing limits on application developers and adding time/space overhead to running applications. We have developed methods, however, to leverage the limited MPUs and thereby reduce overhead cost by narrowing the use of software-based approaches.