diff --git a/sys/net/crosslayer/ng_pktbuf/ng_pktbuf.c b/sys/net/crosslayer/ng_pktbuf/ng_pktbuf.c
index 051790a783..6923fbedb0 100644
--- a/sys/net/crosslayer/ng_pktbuf/ng_pktbuf.c
+++ b/sys/net/crosslayer/ng_pktbuf/ng_pktbuf.c
@@ -46,10 +46,13 @@ int ng_pktbuf_realloc_data(ng_pktsnip_t *pkt, size_t size)
     void *new;
 
     if (pkt == NULL || !_pktbuf_internal_contains(pkt->data)) {
+        DEBUG("pktbuf: (pkt = %p) not in packet buffer\n", (void *)pkt);
         return ENOENT;
     }
 
     if (pkt->users > 1 || pkt->next != NULL) {
+        DEBUG("pktbuf: more than one user (%u) or pkt->next != NULL (%p)\n",
+              pkt->users, (void *)pkt->next);
         return EINVAL;
     }
 
@@ -60,6 +63,7 @@ int ng_pktbuf_realloc_data(ng_pktsnip_t *pkt, size_t size)
     mutex_unlock(&_pktbuf_mutex);
 
     if (new == NULL) {
+        DEBUG("pktbuf: no buffer space for realloc left\n");
         return ENOMEM;
     }
 
@@ -92,6 +96,7 @@ void ng_pktbuf_hold(ng_pktsnip_t *pkt, unsigned int num)
     mutex_lock(&_pktbuf_mutex);
 
     while (pkt != NULL) {
+        DEBUG("pktbuf: hold (pkt = %p) %u times\n", (void *)pkt, num);
         pkt->users += num;
         pkt = pkt->next;
     }
@@ -109,15 +114,18 @@ void ng_pktbuf_release(ng_pktsnip_t *pkt)
 
     while (pkt != NULL) {
         if (pkt->users > 0) {   /* Don't accidentally overshoot */
+            DEBUG("pktbuf: release (pkt = %p)\n", (void *)pkt);
             pkt->users--;
         }
 
         if (pkt->users == 0) {
             if (_pktbuf_internal_contains(pkt->data)) {
+                DEBUG("pktbuf: free pkt->data = %p\n", pkt->data);
                 _pktbuf_internal_free(pkt->data);
             }
 
             if (_pktbuf_internal_contains(pkt)) {
+                DEBUG("pktbuf: free pkt = %p\n", (void *)pkt);
                 _pktbuf_internal_free(pkt);
             }
         }
@@ -135,7 +143,10 @@ ng_pktsnip_t *ng_pktbuf_start_write(ng_pktsnip_t *pkt)
 
         mutex_lock(&_pktbuf_mutex);
 
+        DEBUG("pktbuf: pkt->users = %u => copy-on-write\n", pkt->users);
         res = _pktbuf_duplicate(pkt);
+        DEBUG("pktbuf: copy-on-write result: (pkt = %p) copied to (res = %p)\n",
+              (void *)pkt, (void *)res);
 
         pkt->users--;
 
@@ -156,19 +167,26 @@ static ng_pktsnip_t *_pktbuf_alloc(size_t size)
     ng_pktsnip_t *pkt;
 
     pkt = (ng_pktsnip_t *)_pktbuf_internal_alloc(sizeof(ng_pktsnip_t));
+    DEBUG("pktbuf: allocated (pkt = %p) ", (void *)pkt);
 
     if (pkt == NULL) {
+        DEBUG("=> failed\n");
         return NULL;
     }
 
+    DEBUG("of size %u\n", (unsigned)sizeof(ng_pktsnip_t));
+
     pkt->data = _pktbuf_internal_alloc(size);
+    DEBUG("pktbuf: allocated (pkt->data = %p) ", pkt->data);
 
     if (pkt->data == NULL) {
         _pktbuf_internal_free(pkt);
+        DEBUG("=> failed (freeing %p)\n", (void *)pkt);
 
         return NULL;
     }
 
+    DEBUG("of size %u\n", (unsigned)size);
     pkt->next = NULL;
     pkt->size = size;
     pkt->users = 1;
@@ -182,62 +200,95 @@ static ng_pktsnip_t *_pktbuf_add_unsafe(ng_pktsnip_t *pkt, void *data,
     ng_pktsnip_t *new_pktsnip;
 
     new_pktsnip = (ng_pktsnip_t *)_pktbuf_internal_alloc(sizeof(ng_pktsnip_t));
+    DEBUG("pktbuf: allocated (new_pktsnip = %p) ", (void *)pkt);
 
     if (new_pktsnip == NULL) {
+        DEBUG("=> failed\n");
         return NULL;
     }
 
+    DEBUG("of size %u\n", (unsigned)sizeof(ng_pktsnip_t));
+
     if (pkt == NULL || pkt->data != data) {
         if ((size != 0) && (!_pktbuf_internal_contains(data))) {
             new_pktsnip->data = _pktbuf_internal_alloc(size);
+            DEBUG("pktbuf: allocated (new_pktsnip->data = %p) ", pkt->data);
 
             if (new_pktsnip->data == NULL) {
                 _pktbuf_internal_free(new_pktsnip);
+                DEBUG("=> failed (freeing %p)\n", (void *)pkt);
 
                 return NULL;
             }
 
+            DEBUG("of size %u\n", (unsigned)size);
+
             if (data != NULL) {
+                DEBUG("pktbuf: copying %u byte from %p to %p\n", (unsigned)size,
+                      data, new_pktsnip->data);
                 memcpy(new_pktsnip->data, data, size);
             }
         }
         else {
             if (_pktbuf_internal_contains(data)) {
+                DEBUG("pktbuf: Adding chunk to %p ", new_pktsnip->data);
+
                 if (!_pktbuf_internal_add_pkt(new_pktsnip->data)) {
                     _pktbuf_internal_free(new_pktsnip);
+                    DEBUG("failed (freeing %p)\n", (void *)pkt);
 
                     return NULL;
                 }
+
+                DEBUG("successful\n");
             }
 
             new_pktsnip->data = data;
+            DEBUG("pktbuf: set new_pktsnip->data = %p\n", new_pktsnip->data);
         }
 
         new_pktsnip->next = NULL;
         LL_PREPEND(pkt, new_pktsnip);
+        DEBUG("pktbuf: prepended new_pktsnip to pkt\n");
     }
     else {
         if (size > pkt->size) {
+            DEBUG("pktbuf: new size (%u) out of pkt's boundaries (pkt->size = %u)",
+                  (unsigned)size, (unsigned)pkt->size);
             return NULL;
         }
 
         new_pktsnip->next = pkt->next;
         new_pktsnip->data = data;
+        DEBUG("pktbuf: set new_pktsnip->data = %p\n", new_pktsnip->data);
 
+        DEBUG("pktbuf: add new_pktsnip (%p) to pkt (%p) after head\n",
+              (void *)new_pktsnip, (void *)pkt);
         pkt->next = new_pktsnip;
         pkt->size -= size;
+        DEBUG("pktbuf: resize pkt->size to %u\n", (unsigned)pkt->size);
         pkt->data = (void *)(((uint8_t *)pkt->data) + size);
+        DEBUG("pktbuf: move pkt->data to %p\n", pkt->data);
+
+        DEBUG("pktbuf: Adding chunk to %p ", pkt->data);
 
         if (!_pktbuf_internal_add_pkt(pkt->data)) {
+            DEBUG("failed (freeing %p)\n", (void *)new_pktsnip);
             _pktbuf_internal_free(new_pktsnip);
 
             return NULL;
         }
+
+        DEBUG("successful\n");
     }
 
     new_pktsnip->size = size;
     new_pktsnip->type = type;
     new_pktsnip->users = 1;
+    DEBUG("pktbuf: summary of new snip %p: next = %p, data = %p, size = %u, "
+          "type = %d, users: %u\n", (void *)new_pktsnip, (void *)new_pktsnip->next,
+          new_pktsnip->data, (unsigned)new_pktsnip->size, new_pktsnip->type,
+          new_pktsnip->users);
 
     return new_pktsnip;
 }