diff --git a/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c b/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
index 72da35e8d7..4d89ec1941 100644
--- a/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
+++ b/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
@@ -376,27 +376,6 @@ static int _fill_ipv6_hdr(kernel_pid_t iface, gnrc_pktsnip_t *ipv6,
 
     DEBUG("ipv6: calculate checksum for upper header.\n");
 
-#if GNRC_NETIF_NUMOF > 1
-    if (payload->users > 1) {
-        gnrc_pktsnip_t *ptr = ipv6;
-
-        /* We deal with multiple interfaces here (multicast) => possible
-         * different source addresses => duplication of payload needed */
-        while (ptr != payload->next) {
-            gnrc_pktsnip_t *old = ptr->next;
-            /* duplicate everything including payload */
-            ptr->next = gnrc_pktbuf_start_write(ptr->next);
-
-            if (ptr->next == NULL) {
-                DEBUG("ipv6: unable to get write access to payload, drop it\n");
-                return -ENOBUFS;
-            }
-
-            ptr = old;
-        }
-    }
-#endif /* GNRC_NETIF_NUMOF */
-
     if ((res = gnrc_netreg_calc_csum(payload, ipv6)) < 0) {
         if (res != -ENOENT) {   /* if there is no checksum we are okay */
             DEBUG("ipv6: checksum calculation failed.\n");
@@ -439,6 +418,7 @@ static void _send_multicast(kernel_pid_t iface, gnrc_pktsnip_t *pkt,
 #if GNRC_NETIF_NUMOF > 1
     /* netif header not present: send over all interfaces */
     if (iface == KERNEL_PID_UNDEF) {
+        assert(pkt == ipv6);
         /* send packet to link layer */
         gnrc_pktbuf_hold(pkt, ifnum - 1);
 
@@ -447,7 +427,9 @@ static void _send_multicast(kernel_pid_t iface, gnrc_pktsnip_t *pkt,
             if (prep_hdr) {
                 /* need to get second write access (duplication) to fill IPv6
                  * header interface-local */
-                ipv6 = gnrc_pktbuf_start_write(ipv6);
+                gnrc_pktsnip_t *tmp = gnrc_pktbuf_start_write(pkt);
+                gnrc_pktsnip_t *ptr = tmp->next;
+                ipv6 = tmp;
 
                 if (ipv6 == NULL) {
                     DEBUG("ipv6: unable to get write access to IPv6 header, "
@@ -456,9 +438,23 @@ static void _send_multicast(kernel_pid_t iface, gnrc_pktsnip_t *pkt,
                     return;
                 }
 
-                if (_fill_ipv6_hdr(ifs[i], ipv6, payload) < 0) {
+                /* multiple interfaces => possibly different source addresses
+                 * => different checksums => duplication of payload needed */
+                while (ptr != payload->next) {
+                    /* duplicate everything including payload */
+                    tmp->next = gnrc_pktbuf_start_write(ptr);
+                    if (tmp->next == NULL) {
+                        DEBUG("ipv6: unable to get write access to payload, drop it\n");
+                        gnrc_pktbuf_release(ipv6);
+                        return;
+                    }
+                    tmp = tmp->next;
+                    ptr = ptr->next;
+                }
+
+                if (_fill_ipv6_hdr(ifs[i], ipv6, tmp) < 0) {
                     /* error on filling up header */
-                    gnrc_pktbuf_release(pkt);
+                    gnrc_pktbuf_release(ipv6);
                     return;
                 }
             }
@@ -469,17 +465,18 @@ static void _send_multicast(kernel_pid_t iface, gnrc_pktsnip_t *pkt,
             if (netif == NULL) {
                 DEBUG("ipv6: error on interface header allocation, "
                       "dropping packet\n");
-                gnrc_pktbuf_release(pkt);
+                gnrc_pktbuf_release(ipv6);
                 return;
             }
 
-            LL_PREPEND(pkt, netif);
+            LL_PREPEND(ipv6, netif);
 
             _send_multicast_over_iface(ifs[i], ipv6);
         }
     }
     else {
         /* iface != KERNEL_PID_UNDEF implies that netif header is present */
+        assert(pkt != ipv6);
         if (prep_hdr) {
             if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
                 /* error on filling up header */