diff --git a/drivers/net/mmnif.c b/drivers/net/mmnif.c
index de6b1e48..968e78db 100644
--- a/drivers/net/mmnif.c
+++ b/drivers/net/mmnif.c
@@ -85,7 +85,12 @@
  *  regarding the driver & its configuration
  */
 
-#define MMNIF_RX_BUFFERLEN		32*1024
+#if MMNIF_USE_MPB
+#define MMNIF_RX_BUFFERLEN		7*1024
+#else
+#define MMNIF_RX_BUFFERLEN		8*1024
+#endif
+
 #define MMNIF_MAX_DESCRIPTORS           64
 
 #define MMNIF_CORES                     2
@@ -429,6 +434,7 @@ static uint32_t mmnif_rxbuff_alloc(uint8_t dest, uint16_t len)
 //            if ((rb->head - rb->tail < len)&&(rb->tail != rb->head))
 //                return NULL;
 
+	RCCE_acquire_lock(dest-1);
 	spinlock_lock(&rb->dlock);
 	if (rb->dcount)
 	{
@@ -444,6 +450,7 @@ static uint32_t mmnif_rxbuff_alloc(uint8_t dest, uint16_t len)
 				rb->dwrite = (rb->dwrite + 1) % MMNIF_MAX_DESCRIPTORS;
 				rb->tail = (rb->tail + len);
 				spinlock_unlock(&rb->dlock);
+				RCCE_release_lock(dest-1);
 				return ret;
 			} else if (rb->head > len) {
 				rb->desc_table[rb->dwrite].stat = MMNIF_STATUS_PENDING;
@@ -454,9 +461,11 @@ static uint32_t mmnif_rxbuff_alloc(uint8_t dest, uint16_t len)
 				rb->dwrite = (rb->dwrite + 1) % MMNIF_MAX_DESCRIPTORS;
 				rb->tail = len;
 				spinlock_unlock(&rb->dlock);
+				RCCE_release_lock(dest-1);
 				return ret;
 			} else {
 				spinlock_unlock(&rb->dlock);
+				RCCE_release_lock(dest-1);
 				return 0;
 			}
 		} else {
@@ -470,6 +479,7 @@ static uint32_t mmnif_rxbuff_alloc(uint8_t dest, uint16_t len)
 				rb->dwrite = (rb->dwrite + 1) % MMNIF_MAX_DESCRIPTORS;
 				rb->tail = (rb->tail + len);
 				spinlock_unlock(&rb->dlock);
+				RCCE_release_lock(dest-1);
 				return ret;
 			} else if (rb->tail == rb->head) {
 				if (MMNIF_RX_BUFFERLEN - rb->tail < len)
@@ -486,14 +496,17 @@ static uint32_t mmnif_rxbuff_alloc(uint8_t dest, uint16_t len)
 				rb->dwrite = (rb->dwrite + 1) % MMNIF_MAX_DESCRIPTORS;
 				rb->tail = (rb->tail + len);
 				spinlock_unlock(&rb->dlock);
+				RCCE_release_lock(dest-1);
 				return ret;
 			} else {
 				spinlock_unlock(&rb->dlock);
+				RCCE_release_lock(dest-1);
 				return 0;
 			}
 		}
 	} else {
 		spinlock_unlock(&rb->dlock);
+		RCCE_release_lock(dest-1);
 		return 0;
 	}
 }
@@ -554,6 +567,7 @@ static void mmnif_rxbuff_free(void)
 	uint32_t i, j;
 	uint32_t rpos;
 
+	RCCE_acquire_lock(RCCE_ue());
 	spinlock_lock(&b->dlock);
 	rpos = b->dread;
 
@@ -580,7 +594,9 @@ static void mmnif_rxbuff_free(void)
 		} else
 			break;
 	}
+
 	spinlock_unlock(&b->dlock);
+	RCCE_release_lock(RCCE_ue());
 }
 
 /*
@@ -593,7 +609,7 @@ static err_t mmnif_tx(struct netif *netif, struct pbuf *p)
 	uint32_t i;
 	struct pbuf *q;		/* interator */
 	uint32_t dest_ip = mmnif_get_destination(netif, p);
-	int8_t chances = 20;
+	int8_t chances = 40;
 
 	/* check for over/underflow */
  	if (BUILTIN_EXPECT((p->tot_len < 20 /* IP header size */) || (p->tot_len > 1536), 0)) {
@@ -608,23 +624,18 @@ realloc:
 	{
 		//DEBUGPRINTF("mmnif_tx(): concurrency");
 
-		if (chances <= 0)
-			goto drop_packet;
+		//if (chances <= 0)
+		//	goto drop_packet;
 
-		chances--;
+		//chances--;
 		//mmnif_trigger_irq(dest_ip);
-		NOP8;NOP8;NOP8;NOP8;NOP8;NOP8;NOP8;NOP8;
+		//NOP8;NOP8;NOP8;NOP8;NOP8;NOP8;NOP8;NOP8;
 		goto realloc;
 	}
 
 	if (!write_address)
 		goto drop_packet;
 
-	/* write buffer to buffer & increment the queued packet count 
-	 * this can be safely done without locking because this place is
-	 * reserved for us because it has the status "pending"
-	 */
-
 #if MMNIF_USE_MPB
 	asm volatile (".byte 0x0f; .byte 0x0a;\n");
 #endif
@@ -634,7 +645,7 @@ realloc:
 #if MMNIF_USE_MPB
 		memcpy_put((char*) write_address + i, q->payload, q->len);
 #else
-		memcpy((char*)write_address+ i, q->payload, q->len);
+		memcpy((char*) write_address+ i, q->payload, q->len);
 #endif
 		i += q->len;
 	}