diff --git a/hermit/drivers/net/mmnif.c b/hermit/drivers/net/mmnif.c
index d91d58284..9dcb7276f 100644
--- a/hermit/drivers/net/mmnif.c
+++ b/hermit/drivers/net/mmnif.c
@@ -849,11 +849,16 @@ static void mmnif_irqhandler(struct state* s)
 
 	mmnif = (mmnif_t *) mmnif_dev->state;
 	if (!mmnif->check_in_progress) {
+#if LWIP_TCPIP_CORE_LOCKING_INPUT
+		mmnif->check_in_progress = 1;
+		mmnif_rx(mmnif_dev);
+#else
 		if (tcpip_callback_with_block((tcpip_callback_fn) mmnif_rx, (void*) mmnif_dev, 0) == ERR_OK) {
 			mmnif->check_in_progress = 1;
 		} else {
-			DEBUGPRINTF("rckemacif_handler: unable to send a poll request to the tcpip thread\n");
+			DEBUGPRINTF("mmnif_handler: unable to send a poll request to the tcpip thread\n");
 		}
+#endif
 	}
 }
 
diff --git a/hermit/kernel/main.c b/hermit/kernel/main.c
index c1860b191..d0cc85417 100644
--- a/hermit/kernel/main.c
+++ b/hermit/kernel/main.c
@@ -172,10 +172,16 @@ static int init_netifs(void)
 	 *  - gw : the gateway wicht should be used
 	 *  - mmnif_init : the initialization which has to be done in order to use our interface
 	 *  - ip_input : tells him that he should use ip_input
-	 *
+	 */
+#if LWIP_TCPIP_CORE_LOCKING_INPUT
+	if ((err = netifapi_netif_add(&mmnif_netif, &ipaddr, &netmask, &gw, NULL, mmnif_init, tcpip_input)) != ERR_OK)
+#else
+	/*
 	 * Note: Our drivers guarantee that the input function will be called in the context of the tcpip thread.
-	 * => Therefore, we are able to use ip_input instead of tcpip_input */
+	 * => Therefore, we are able to use ip_input instead of tcpip_input
+	 */
         if ((err = netifapi_netif_add(&mmnif_netif, &ipaddr, &netmask, &gw, NULL, mmnif_init, ip_input)) != ERR_OK)
+#endif
         {
                 kprintf("Unable to add the intra network interface: err = %d\n", err);
                 return -ENODEV;
diff --git a/hermit/lwip b/hermit/lwip
index 3a11d4209..12edcefed 160000
--- a/hermit/lwip
+++ b/hermit/lwip
@@ -1 +1 @@
-Subproject commit 3a11d42097b7008ffd1b3ceac1e414dcc74a2228
+Subproject commit 12edcefed1a4e30a91ff969b5aa4630b2f7c7651