diff --git a/include/satnogs/ax25.h b/include/satnogs/ax25.h
index 3d4965a..1c0d543 100644
--- a/include/satnogs/ax25.h
+++ b/include/satnogs/ax25.h
@@ -122,7 +122,7 @@ namespace gr
       *out++ = ((0b1111 & dest_ssid) << 1) | 0b01100000;
 
       for (i = 0; i < src_addr.length (); i++) {
-        *out++ = dest_addr[i] << 1;
+        *out++ = src_addr[i] << 1;
       }
       for (; i < AX25_CALLSIGN_MAX_LEN; i++) {
         *out++ = ' ' << 1;
@@ -131,7 +131,7 @@ namespace gr
        * the trailing bit is set to 1.
        * /
        /* FIXME: C bit is set to 0 implicitly */
-      *out++ = ((0b1111 & dest_ssid) << 1) | 0b01100001;
+      *out++ = ((0b1111 & src_ssid) << 1) | 0b01100001;
       return AX25_MIN_ADDR_LEN;
     }
 
diff --git a/lib/ax25_decoder_bm_impl.cc b/lib/ax25_decoder_bm_impl.cc
index 3dee14a..7b84a09 100644
--- a/lib/ax25_decoder_bm_impl.cc
+++ b/lib/ax25_decoder_bm_impl.cc
@@ -133,6 +133,11 @@ namespace gr
             else{
               d_decoded_bits++;
               if(d_decoded_bits == 8) {
+                /* Check if the received byte is valid */
+                if(!check_byte()) {
+                  reset_state ();
+                  return i + 1;
+                }
                 d_frame_buffer[d_received_bytes] = d_dec_b;
                 d_received_bytes++;
                 d_decoded_bits = 0;
@@ -226,6 +231,11 @@ namespace gr
             else {
               d_decoded_bits++;
               if (d_decoded_bits == 8) {
+                /* Check if the received byte is valid */
+                if(!check_byte()) {
+                  reset_state ();
+                  return i + 1;
+                }
                 d_frame_buffer[d_received_bytes] = d_dec_b;
                 d_received_bytes++;
                 d_decoded_bits = 0;
@@ -338,8 +348,6 @@ namespace gr
 
       /* First check if the size of the frame is valid */
       if (d_received_bytes < AX25_MIN_ADDR_LEN + sizeof(uint16_t)) {
-        message_port_pub (pmt::mp ("failed_pdu"),
-                          pmt::make_blob (d_frame_buffer, d_received_bytes));
         d_dec_b = 0x0;
         d_shift_reg = 0x0;
         d_decoded_bits = 0;
@@ -417,6 +425,30 @@ namespace gr
       d_dec_b = (d_dec_b >> 1) | (dec_bit << 7);
     }
 
+    /**
+     * Checks if a AX.25 decoded byte is valid. This actually can be checked
+     * only in the address field, where all fields should have the LS bit
+     * set to zero.
+     * @returns true if the decoded byte is valid, false otherwise
+     */
+    inline bool
+    ax25_decoder_bm_impl::check_byte ()
+    {
+      if(d_received_bytes < AX25_MIN_ADDR_LEN - 1) {
+        if(d_dec_b & 0x1) {
+          return false;
+        }
+      }
+      else if(d_received_bytes == AX25_MIN_ADDR_LEN - 1) {
+        if(d_dec_b & 0x1) {
+          return true;
+        }
+        return false;
+      }
+      return true;
+    }
+
+
     int
     ax25_decoder_bm_impl::work (int noutput_items,
                                 gr_vector_const_void_star &input_items,
diff --git a/lib/ax25_decoder_bm_impl.h b/lib/ax25_decoder_bm_impl.h
index 86ba005..637e6ce 100644
--- a/lib/ax25_decoder_bm_impl.h
+++ b/lib/ax25_decoder_bm_impl.h
@@ -72,6 +72,8 @@ namespace gr
       descramble_and_decode_1b (uint8_t in);
       inline void
       decode_1b (uint8_t in);
+      inline bool
+      check_byte ();
 
 
     public: