diff --git a/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_eth.c b/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_eth.c
index 22610c3209c..9175a9793a8 100644
--- a/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_eth.c
+++ b/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_eth.c
@@ -33,6 +33,7 @@
 #define ETH_DISABLE_TX()    do{EMAC->CTL &= ~EMAC_CTL_TXON;}while(0)
 #define ETH_DISABLE_RX()    do{EMAC->CTL &= ~EMAC_CTL_RXON;}while(0)
 
+
 /*
 #ifdef __ICCARM__
 #pragma data_alignment=4
@@ -99,7 +100,7 @@ static int reset_phy(void)
     }
 
     if(delay == 0) {
-        printf("Reset phy failed\n");
+        LWIP_DEBUGF(LWIP_DBG_LEVEL_SEVERE|LWIP_DBG_ON,("Reset phy failed\n"));
         return(-1);
     }
 
@@ -120,23 +121,23 @@ static int reset_phy(void)
     }
 
     if(delay == 0) {
-        printf("AN failed. Set to 100 FULL\n");
+        LWIP_DEBUGF(LWIP_DBG_LEVEL_SEVERE|LWIP_DBG_ON , ("AN failed. Set to 100 FULL\n"));
         EMAC->CTL |= (EMAC_CTL_OPMODE_Msk | EMAC_CTL_FUDUP_Msk);
         return(-1);
     } else {
         reg = mdio_read(CONFIG_PHY_ADDR, MII_LPA);
 
         if(reg & ADVERTISE_100FULL) {
-            printf("100 full\n");
+            LWIP_DEBUGF(LWIP_DBG_LEVEL_ALL|LWIP_DBG_ON, ("100 full\n"));
             EMAC->CTL |= (EMAC_CTL_OPMODE_Msk | EMAC_CTL_FUDUP_Msk);
         } else if(reg & ADVERTISE_100HALF) {
-            printf("100 half\n");
+            LWIP_DEBUGF(LWIP_DBG_LEVEL_ALL|LWIP_DBG_ON, ("100 half\n"));
             EMAC->CTL = (EMAC->CTL & ~EMAC_CTL_FUDUP_Msk) | EMAC_CTL_OPMODE_Msk;
         } else if(reg & ADVERTISE_10FULL) {
-            printf("10 full\n");
+            LWIP_DEBUGF(LWIP_DBG_LEVEL_ALL|LWIP_DBG_ON, ("10 full\n"));
             EMAC->CTL = (EMAC->CTL & ~EMAC_CTL_OPMODE_Msk) | EMAC_CTL_FUDUP_Msk;
         } else {
-            printf("10 half\n");
+            LWIP_DEBUGF(LWIP_DBG_LEVEL_ALL|LWIP_DBG_ON, ("10 half\n"));
             EMAC->CTL &= ~(EMAC_CTL_OPMODE_Msk | EMAC_CTL_FUDUP_Msk);
         }
     }
@@ -267,7 +268,7 @@ void EMAC_RX_IRQHandler(void)
     EMAC->INTSTS = m_status;
     if (m_status & EMAC_INTSTS_RXBEIF_Msk) {
         // Shouldn't goes here, unless descriptor corrupted
-		printf("RX descriptor corrupted \r\n");
+		LWIP_DEBUGF(LWIP_DBG_LEVEL_SERIOUS|LWIP_DBG_ON, ("RX descriptor corrupted \r\n"));
 		//return;
     }
 	ack_emac_rx_isr();
diff --git a/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_netif.c b/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_netif.c
index cd480c07fc8..148c2e285ba 100644
--- a/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_netif.c
+++ b/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_NUVOTON/TARGET_NUC472/nuc472_netif.c
@@ -42,7 +42,7 @@
  * search-and-replace for the word "ethernetif" to replace it with
  * something that better describes your network interface.
  */
-
+ 
 #include "lwip/opt.h"
 
 #include "lwip/def.h"
@@ -494,16 +494,15 @@ static void __phy_task(void *data) {
     // Compare with previous state
 			
 			if( !(ETH_link_ok()) && (netif->flags & NETIF_FLAG_LINK_UP) ) {
-				//tcpip_callback_with_block((tcpip_callback_fn)netif_set_link_down, (void*) netif, 1);
+				/* tcpip_callback_with_block((tcpip_callback_fn)netif_set_link_down, (void*) netif, 1); */
 				netif_set_link_down(netif);
-				printf("Link Down\r\n");	
+				LWIP_DEBUGF(LWIP_DBG_LEVEL_WARNING|LWIP_DBG_ON, ("Link Down\r\n"));	
 			}else if ( ETH_link_ok() && !(netif->flags & NETIF_FLAG_LINK_UP) ) { 
-				//tcpip_callback_with_block((tcpip_callback_fn)netif_set_link_up, (void*) netif, 1);
+				/* tcpip_callback_with_block((tcpip_callback_fn)netif_set_link_up, (void*) netif, 1); */
 				netif_set_link_up(netif);
-				printf("Link Up\r\n");
+				LWIP_DEBUGF(LWIP_DBG_LEVEL_WARNING|LWIP_DBG_ON, ("Link Up\r\n"));
 			}
 			
-//	printf("-");
     osDelay(200);
   }
 }