diff --git a/main.c b/main.c
index c2068f4..4206632 100644
--- a/main.c
+++ b/main.c
@@ -79,14 +79,12 @@ int main() {
 
   netif_add(&g_netif, &ipaddr, &netmask, &gw, NULL, &ethernetif_init,
             &ethernet_input);
-
+  //   netif_set_link_callback(&g_netif, link_status_callback);
   netif_set_default(&g_netif);
   netif_set_up(&g_netif);
 
   dhcp_start(&g_netif);
 
-  ethernetif_init(&g_netif);
-
   uint32_t last_led_toggle = 0;
   uint32_t last_send_time = 0;
   int led_state = 0;
diff --git a/port/ethernetif.c b/port/ethernetif.c
index 9659075..29cf070 100644
--- a/port/ethernetif.c
+++ b/port/ethernetif.c
@@ -75,6 +75,10 @@ void ETH_IRQHandler(void) {
   g_isr_call_count++;
   uint8_t flags = ETH10M->EIR;
 
+  if (flags & RB_ETH_EIR_RXIF) {
+    printf("<<< RX Interrupt Fired. EIR=0x%02X >>>>>\n", flags);
+  }
+
   // tx complete/error
   if (flags & (RB_ETH_EIR_TXIF | RB_ETH_EIR_TXERIF)) {
     // release DMA descriptor back to cpu
@@ -113,8 +117,8 @@ static void low_level_init(struct netif* netif) {
 
   // interrupts
   ETH10M->EIE = 0;  // clear
-  ETH10M->EIE = RB_ETH_EIE_INTIE | RB_ETH_EIE_RXIE | RB_ETH_EIE_LINKIE |
-                RB_ETH_EIE_TXIE | RB_ETH_EIE_TXERIE | RB_ETH_EIE_RXERIE;
+  ETH10M->EIE = RB_ETH_EIE_INTIE | RB_ETH_EIE_LINKIE | RB_ETH_EIE_TXIE |
+                RB_ETH_EIE_TXERIE | RB_ETH_EIE_RXERIE;
   ETH10M->EIE |= RB_ETH_EIE_R_EN50;  // 50 ohm pull-up
 
   ETH10M->EIR = 0xFF;
@@ -196,51 +200,52 @@ static err_t low_level_output(struct netif* netif, struct pbuf* p) {
   return ERR_OK;
 }
 
-static struct pbuf* low_level_input(struct netif* netif) {
+struct pbuf* low_level_input(struct netif* netif) {
   struct ethernetif* ethernetif = netif->state;
   struct pbuf *p = NULL, *q;
   u16_t len;
+  ETH_DMADESCTypeDef* dmarxdesc;
+
+  if (ETH10M->EIR & RB_ETH_EIR_RXIF) {
+    dmarxdesc = ethernetif->DMARxDescToGet;
 
-  if ((ethernetif->DMARxDescToGet->Status & ETH_DMARxDesc_OWN) == 0) {
     if (ETH10M->ESTAT & (RB_ETH_ESTAT_BUFER | RB_ETH_ESTAT_RXCRCER)) {
-      len = 0;  // drop packet
-      // printf("RX ESTAT Error: 0x%02X\n", ETH10M->ESTAT);
+      len = 0;
+      printf("HW RX Error ESTAT: 0x%02X\n", (unsigned int)ETH10M->ESTAT);
       ETH10M->ESTAT |= (RB_ETH_ESTAT_BUFER | RB_ETH_ESTAT_RXCRCER);
     } else {
       len = ETH10M->ERXLN;
-      if (len > 4) {
-        len -= 4;
-      } else {
-        len = 0;
-      }
     }
 
-    // copy valid packet to pbuf
     if (len > 0) {
       p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
       if (p != NULL) {
-        uint8_t* rx_buffer = (uint8_t*)ethernetif->DMARxDescToGet->Buffer1Addr;
+        uint8_t* rx_buffer = (uint8_t*)dmarxdesc->Buffer1Addr;
         uint32_t bytes_copied = 0;
         for (q = p; q != NULL; q = q->next) {
           memcpy(q->payload, rx_buffer + bytes_copied, q->len);
           bytes_copied += q->len;
         }
-        MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
+        printf(
+            "\n>>> Packet Received (len=%d, MAC len=%d). Copied to LwIP. "
+            "<<<\n\n",
+            len, ETH10M->ERXLN);
+      } else {
+        printf("pbuf_alloc failed. Dropping packet.\n");
       }
     }
 
-    ethernetif->DMARxDescToGet->Status |= ETH_DMARxDesc_OWN;
-
+    dmarxdesc->Status = ETH_DMARxDesc_OWN;
     ethernetif->DMARxDescToGet =
-        (ETH_DMADESCTypeDef*)ethernetif->DMARxDescToGet->Buffer2NextDescAddr;
+        (ETH_DMADESCTypeDef*)dmarxdesc->Buffer2NextDescAddr;
 
-    // tell hw where next free buffer is?
     ETH10M->ERXST = (uint32_t)ethernetif->DMARxDescToGet->Buffer1Addr;
+    ETH10M->EIR = RB_ETH_EIR_RXIF;
 
-    return p;
+    return p;  // return pbuf to LwIP
   }
 
-  return NULL;  // no packet
+  return NULL;  // No packet was available.
 }
 
 void ethernetif_input(struct netif* netif) {
@@ -290,6 +295,7 @@ err_t ethernetif_init(struct netif* netif) {
 }
 
 void ethernetif_link_poll(struct netif* netif) {
+  struct ethernetif* ethernetif = netif->state;
   static uint32_t last_poll_time = 0;
   uint32_t now = millis();
 
@@ -305,6 +311,7 @@ void ethernetif_link_poll(struct netif* netif) {
     if (!netif_is_link_up(netif)) {
       printf("Link is UP (10M-FD Mode)\n");
 
+      ETH10M->ERXST = (uint32_t)ethernetif->DMARxDescToGet->Buffer1Addr;
       ETH10M->ECON1 |= RB_ETH_ECON1_RXEN;
 
       netif_set_link_up(netif);
diff --git a/port/lwipopts.h b/port/lwipopts.h
index 050987c..5551785 100644
--- a/port/lwipopts.h
+++ b/port/lwipopts.h
@@ -4,9 +4,11 @@
 #define LWIP_DEBUG 1
 #define LWIP_DBG_MIN_LEVEL LWIP_DBG_LEVEL_ALL
 
-#define DHCP_DEBUG     LWIP_DBG_ON
-#define NETIF_DEBUG    LWIP_DBG_ON
-#define ETHARP_DEBUG   LWIP_DBG_ON
+#define UDP_DEBUG LWIP_DBG_ON
+#define IP_DEBUG LWIP_DBG_ON
+#define DHCP_DEBUG LWIP_DBG_ON
+#define NETIF_DEBUG LWIP_DBG_ON
+#define ETHARP_DEBUG LWIP_DBG_ON
 
 #define NO_SYS 1
 
@@ -40,7 +42,7 @@
 // #define CHECKSUM_GEN_UDP              0
 // #define CHECKSUM_GEN_TCP              0
 // #define CHECKSUM_CHECK_IP             0
-// #define CHECKSUM_CHECK_UDP            0
+#define CHECKSUM_CHECK_UDP 0
 // #define CHECKSUM_CHECK_TCP            0
 // #define LWIP_CHECKSUM_ON_COPY         1
 
@@ -50,4 +52,6 @@
 // Statistics
 #define LWIP_STATS 0
 
+#define LWIP_NETIF_LINK_CALLBACK 1
+
 #endif /* __LWIPOPTS_H__ */