diff --git a/sys/arm/at91/at91_mci.c b/sys/arm/at91/at91_mci.c
index 196aa641ad9b..9a1bb31e7132 100644
--- a/sys/arm/at91/at91_mci.c
+++ b/sys/arm/at91/at91_mci.c
@@ -299,7 +299,7 @@ at91_mci_deactivate(device_t dev)
 	sc->intrhand = 0;
 	bus_generic_detach(sc->dev);
 	if (sc->mem_res)
-		bus_release_resource(dev, SYS_RES_IOPORT,
+		bus_release_resource(dev, SYS_RES_MEMORY,
 		    rman_get_rid(sc->mem_res), sc->mem_res);
 	sc->mem_res = 0;
 	if (sc->irq_res)