L4 is a small microkernel that is used as a basis for several operating systems. L4 seems an ideal basis for embedded systems that possess and use memory protection. It could provide a reliable, robust, and secure embedded platform. This paper examines L4’s suitability as a basis for trustworthy embedded systems. It motivates the use of a microkernel, introduces L4 in particular as an example microkernel, overviews selected embedded applications benefiting from memory protection (focusing mostly on security related applications), and then examines L4’s applicability to those application domains and identifies issues with L4’s abstractions and mechanisms.