Electronic systems that enable programmable transformation of functional behaviors by remote control or by autonomous responses to user-defined circumstances create unusual engineering opportunities, where physical changes in the hardware induce desired changes in operation. This paper presents materials and device architectures for technologies of this type, in which localized microfluidic chemical etching of targeted constituent components in the electronics occurs in a sequential, selective manner. Custom circuits that include reconfigurable radio-powered thermal actuators with analog amplifiers and square waveform generators illustrate the concepts.