diff --git a/sys/dev/uart/uart_dev_quicc.c b/sys/dev/uart/uart_dev_quicc.c
index bd735f2da6f4..d6a8846b874e 100644
--- a/sys/dev/uart/uart_dev_quicc.c
+++ b/sys/dev/uart/uart_dev_quicc.c
@@ -412,7 +412,6 @@ quicc_bus_param(struct uart_softc *sc, int baudrate, int databits,
 static int
 quicc_bus_probe(struct uart_softc *sc)
 {
-	char buf[80];
 	int error;
 
 	error = quicc_probe(&sc->sc_bas);
@@ -422,8 +421,7 @@ quicc_bus_probe(struct uart_softc *sc)
 	sc->sc_rxfifosz = 1;
 	sc->sc_txfifosz = 1;
 
-	snprintf(buf, sizeof(buf), "quicc, channel %d", sc->sc_bas.chan);
-	device_set_desc_copy(sc->sc_dev, buf);
+	device_set_descf(sc->sc_dev, "quicc, channel %d", sc->sc_bas.chan);
 	return (0);
 }
 
diff --git a/sys/dev/uart/uart_dev_z8530.c b/sys/dev/uart/uart_dev_z8530.c
index 2ca480a5690d..45bf63f20bb2 100644
--- a/sys/dev/uart/uart_dev_z8530.c
+++ b/sys/dev/uart/uart_dev_z8530.c
@@ -509,7 +509,6 @@ z8530_bus_param(struct uart_softc *sc, int baudrate, int databits,
 static int
 z8530_bus_probe(struct uart_softc *sc)
 {
-	char buf[80];
 	int error;
 	char ch;
 
@@ -522,8 +521,7 @@ z8530_bus_probe(struct uart_softc *sc)
 
 	ch = sc->sc_bas.chan - 1 + 'A';
 
-	snprintf(buf, sizeof(buf), "z8530, channel %c", ch);
-	device_set_desc_copy(sc->sc_dev, buf);
+	device_set_descf(sc->sc_dev, "z8530, channel %c", ch);
 	return (0);
 }