diff --git a/core/net/mac/contikimac/contikimac.c b/core/net/mac/contikimac/contikimac.c
index 229cfb473..7088e8e54 100644
--- a/core/net/mac/contikimac/contikimac.c
+++ b/core/net/mac/contikimac/contikimac.c
@@ -873,6 +873,10 @@ qsend_list(mac_callback_t sent, void *ptr, struct rdc_buf_list *buf_list)
       if(next != NULL) {
         packetbuf_set_attr(PACKETBUF_ATTR_PENDING, 1);
       }
+#if !NETSTACK_CONF_BRIDGE_MODE
+      /* If NETSTACK_CONF_BRIDGE_MODE is set, assume PACKETBUF_ADDR_SENDER is already set. */
+      packetbuf_set_addr(PACKETBUF_ADDR_SENDER, &linkaddr_node_addr);
+#endif
       packetbuf_set_attr(PACKETBUF_ATTR_MAC_ACK, 1);
       if(NETSTACK_FRAMER.create() < 0) {
         PRINTF("contikimac: framer failed\n");
diff --git a/core/net/mac/framer-802154.c b/core/net/mac/framer-802154.c
index 35e39cf33..86f550fd1 100644
--- a/core/net/mac/framer-802154.c
+++ b/core/net/mac/framer-802154.c
@@ -173,7 +173,8 @@ create_frame(int type, int do_create)
    * Set up the source address using only the long address mode for
    * phase 1.
    */
-  linkaddr_copy((linkaddr_t *)&params.src_addr, &linkaddr_node_addr);
+  linkaddr_copy((linkaddr_t *)&params.src_addr,
+                packetbuf_addr(PACKETBUF_ADDR_SENDER));
 
   params.payload = packetbuf_dataptr();
   params.payload_len = packetbuf_datalen();
diff --git a/core/net/mac/tsch/tsch.c b/core/net/mac/tsch/tsch.c
index a31d4a1ae..348406dac 100644
--- a/core/net/mac/tsch/tsch.c
+++ b/core/net/mac/tsch/tsch.c
@@ -910,6 +910,15 @@ send_packet(mac_callback_t sent, void *ptr)
 
   packet_count_before = tsch_queue_packet_count(addr);
 
+#if !NETSTACK_CONF_BRIDGE_MODE
+  /*
+   * In the Contiki stack, the source address of a frame is set at the RDC
+   * layer. Since TSCH doesn't use any RDC protocol and bypasses the layer to
+   * transmit a frame, it should set the source address by itself.
+   */
+  packetbuf_set_addr(PACKETBUF_ADDR_SENDER, &linkaddr_node_addr);
+#endif
+
   if((hdr_len = NETSTACK_FRAMER.create()) < 0) {
     PRINTF("TSCH:! can't send packet due to framer error\n");
     ret = MAC_TX_ERR;