Abstract: Reconfigurable systems have benefited of the novel partial dynamic reconfiguration features of recent FPGA devices. Enabling the concurrent reconfiguration without disturbing system operation, this technology has raised a new test challenge: to assure a continuously fault free operation, independently of the circuit present after many reconfiguration processes, testing the FPGA without disturbing the whole system operation. Re-using the IEEE 1149.1 infrastructure, already widely used for In-System Programming, and exploiting the same dynamic and partially reconfigurable features underlying this test challenge, this paper develops a new structural concurrent test approach able to detect faults and introduce fault tolerance features, without disturbing system operation, in the field and throughout its lifetime.