Supporting dynamic reconfiguration is required even in highly constrained embedded systems, to allow software patches and updates, and to allow adaptations to changes in environmental and operating conditions without service interruption. Dynamic reconfiguration, however, is a complex and error prone process. In this paper we report our experience in implementing safe dynamic reconfigurations in embedded devices with limited resources. Our approach relies on a component-based framework for building reconfigurable operating systems, and the use of a domain specific language (DSL) for reconfiguration.