diff --git a/bin/mbus-serial-request-data-multi-reply.c b/bin/mbus-serial-request-data-multi-reply.c
index 9dd1648..36831bc 100644
--- a/bin/mbus-serial-request-data-multi-reply.c
+++ b/bin/mbus-serial-request-data-multi-reply.c
@@ -98,10 +98,10 @@ main(int argc, char **argv)
     }
     
     frame->control = MBUS_CONTROL_MASK_SND_NKE | MBUS_CONTROL_MASK_DIR_M2S;
-    frame->address = MBUS_ADDRESS_BROADCAST_NOREPLY;
+    frame->address = MBUS_ADDRESS_NETWORK_LAYER;
     
     if (debug)
-        printf("%s: debug: sending init frame\n", __PRETTY_FUNCTION__);
+        printf("%s: debug: sending init frame #1\n", __PRETTY_FUNCTION__);
     
     if (mbus_send_frame(handle, frame) == -1)
     {
@@ -110,8 +110,27 @@ main(int argc, char **argv)
         return 1;
     }
     
-    mbus_recv_frame(handle, &reply);
+    while (mbus_recv_frame(handle, &reply) != -1);
     
+    //
+    // resend SND_NKE, maybe the first get lost
+    //
+    
+    frame->control = MBUS_CONTROL_MASK_SND_NKE | MBUS_CONTROL_MASK_DIR_M2S;
+    frame->address = MBUS_ADDRESS_NETWORK_LAYER;
+
+    if (debug)
+        printf("%s: debug: sending init frame #2\n", __PRETTY_FUNCTION__);
+
+    if (mbus_send_frame(handle, frame) == -1)
+    {
+        fprintf(stderr, "Failed to send mbus frame.\n");
+        mbus_frame_free(frame);
+        return 1;
+    }
+
+    while (mbus_recv_frame(handle, &reply) != -1);
+
     if (strlen(addr_str) == 16)
     {
         // secondary addressing
@@ -147,7 +166,7 @@ main(int argc, char **argv)
     
     // instead of the send and recv, use this sendrecv function that 
     // takes care of the possibility of multi-telegram replies (limit = 16 frames)
-    if (mbus_sendrecv_request(handle, address, &reply, 16) == -1)
+    if (mbus_sendrecv_request(handle, address, &reply, 16) != 0)
     {
         fprintf(stderr, "Failed to send/receive M-Bus request.\n");
         return 1;
diff --git a/bin/mbus-serial-request-data.c b/bin/mbus-serial-request-data.c
index d60a777..219a49d 100644
--- a/bin/mbus-serial-request-data.c
+++ b/bin/mbus-serial-request-data.c
@@ -126,7 +126,7 @@ main(int argc, char **argv)
         }
     }   
 
-    if (mbus_recv_frame(handle, &reply) == -1)
+    if (mbus_recv_frame(handle, &reply) != 0)
     {
         fprintf(stderr, "Failed to receive M-Bus response frame.\n");
         return 1;
diff --git a/bin/mbus-serial-scan-secondary.c b/bin/mbus-serial-scan-secondary.c
index 92dc3d3..960c066 100644
--- a/bin/mbus-serial-scan-secondary.c
+++ b/bin/mbus-serial-scan-secondary.c
@@ -127,7 +127,7 @@ main(int argc, char **argv)
     // init slaves
     //
     frame->control = MBUS_CONTROL_MASK_SND_NKE | MBUS_CONTROL_MASK_DIR_M2S;
-    frame->address = 0xFD;
+    frame->address = MBUS_ADDRESS_NETWORK_LAYER;
 
     if (mbus_send_frame(handle, frame) == -1)
     {
@@ -139,7 +139,7 @@ main(int argc, char **argv)
     (void) mbus_recv_frame(handle, &reply);
 
     frame->control = MBUS_CONTROL_MASK_SND_NKE | MBUS_CONTROL_MASK_DIR_M2S;
-    frame->address = 0xFF;
+    frame->address = MBUS_ADDRESS_BROADCAST_NOREPLY;
 
     if (mbus_send_frame(handle, frame) == -1)
     {
diff --git a/bin/mbus-tcp-request-data-multi-reply.c b/bin/mbus-tcp-request-data-multi-reply.c
index e06c022..7c165c0 100644
--- a/bin/mbus-tcp-request-data-multi-reply.c
+++ b/bin/mbus-tcp-request-data-multi-reply.c
@@ -130,7 +130,7 @@ main(int argc, char **argv)
     
     // instead of the send and recv, use this sendrecv function that 
     // takes care of the possibility of multi-telegram replies (limit = 16 frames)
-    if (mbus_sendrecv_request(handle, address, &reply, 16) == -1)
+    if (mbus_sendrecv_request(handle, address, &reply, 16) != 0)
     {
         fprintf(stderr, "Failed to send/receive M-Bus request.\n");
         return 1;
diff --git a/bin/mbus-tcp-request-data.c b/bin/mbus-tcp-request-data.c
index 7b40f28..fce7b7b 100644
--- a/bin/mbus-tcp-request-data.c
+++ b/bin/mbus-tcp-request-data.c
@@ -111,7 +111,7 @@ main(int argc, char **argv)
         }
     }   
 
-    if (mbus_recv_frame(handle, &reply) == -1)
+    if (mbus_recv_frame(handle, &reply) != 0)
     {
         fprintf(stderr, "Failed to receive M-Bus response frame.\n");
         return 1;
diff --git a/bin/mbus-tcp-scan-secondary.c b/bin/mbus-tcp-scan-secondary.c
index e2cca2a..6a97484 100644
--- a/bin/mbus-tcp-scan-secondary.c
+++ b/bin/mbus-tcp-scan-secondary.c
@@ -75,7 +75,7 @@ main(int argc, char **argv)
     // init slaves
     //
     frame->control = MBUS_CONTROL_MASK_SND_NKE | MBUS_CONTROL_MASK_DIR_M2S;
-    frame->address = 0xFD;
+    frame->address = MBUS_ADDRESS_NETWORK_LAYER;
 
     if (mbus_send_frame(handle, frame) == -1)
     {
@@ -88,7 +88,7 @@ main(int argc, char **argv)
     sleep(1);
 
     frame->control = MBUS_CONTROL_MASK_SND_NKE | MBUS_CONTROL_MASK_DIR_M2S;
-    frame->address = 0xFF;
+    frame->address = MBUS_ADDRESS_BROADCAST_NOREPLY;
 
     if (mbus_send_frame(handle, frame) == -1)
     {
diff --git a/mbus/mbus-protocol-aux.c b/mbus/mbus-protocol-aux.c
index 2323bec..bba0cbc 100644
--- a/mbus/mbus-protocol-aux.c
+++ b/mbus/mbus-protocol-aux.c
@@ -1389,6 +1389,12 @@ mbus_recv_frame(mbus_handle * handle, mbus_frame *frame)
         return 0;
     }
 
+    if (frame == NULL)
+    {
+        MBUS_ERROR("%s: Invalid frame.\n", __PRETTY_FUNCTION__);
+        return 0;
+    }
+
     if (handle->is_serial)
     {
         result = mbus_serial_recv_frame(handle->m_serial_handle, frame);    
@@ -1594,6 +1600,8 @@ mbus_sendrecv_request(mbus_handle *handle, int address, mbus_frame *reply, int m
     //
     next_frame = reply;
     
+    memset((void *)&reply_data, 0, sizeof(mbus_frame_data));
+    
     while (more_frames)
     {
         frame_count++;
@@ -1601,7 +1609,7 @@ mbus_sendrecv_request(mbus_handle *handle, int address, mbus_frame *reply, int m
         if (debug)
             printf("%s: debug: receiving response frame #%d\n", __PRETTY_FUNCTION__, frame_count);
     
-        if (mbus_recv_frame(handle, next_frame) == -1)
+        if (mbus_recv_frame(handle, next_frame) != 0)
         {
             MBUS_ERROR("%s: Failed to receive M-Bus response frame.\n", __PRETTY_FUNCTION__);
             retval = 1;
@@ -1905,7 +1913,7 @@ int mbus_read_slave(mbus_handle * handle, mbus_address *address, mbus_frame * re
         }
     } 
 
-    if (mbus_recv_frame(handle, reply) == -1)
+    if (mbus_recv_frame(handle, reply) != 0)
     {
         MBUS_ERROR("%s: Failed to receive M-Bus response frame.\n",
                    __PRETTY_FUNCTION__);