diff --git a/openbsc/src/libmgcp/mgcp_sdp.c b/openbsc/src/libmgcp/mgcp_sdp.c
index 33837b9..aa4ef30 100644
--- a/openbsc/src/libmgcp/mgcp_sdp.c
+++ b/openbsc/src/libmgcp/mgcp_sdp.c
@@ -159,6 +159,9 @@
 	char *bts_codec;
 	char audio_codec[64];
 
+	if (!codec->codec_name)
+		return 0;
+
 	/*
 	 * GSM, GSM/8000 and GSM/8000/1 should all be compatible.. let's go
 	 * by name first.
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index d501859..df2ab29 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -350,7 +350,7 @@
 		"v=0\r\n"				\
 		"o=- 1439038275 1439038275 IN IP4 192.168.181.247\r\n" \
 		"s=-\r\nc=IN IP4 192.168.181.247\r\n"	\
-		"t=0 0\r\nm=audio 29084 RTP/AVP 0 8 3 18 4 96 97 101\r\n" \
+		"t=0 0\r\nm=audio 29084 RTP/AVP 255 0 8 3 18 4 96 97 101\r\n" \
 		"a=rtpmap:0 PCMU/8000\r\n"		\
 		"a=rtpmap:8 PCMA/8000\r\n"		\
 		"a=rtpmap:3 gsm/8000\r\n"		\
@@ -1068,8 +1068,8 @@
 
 	OSMO_ASSERT(last_endpoint == 5);
 	endp = &cfg->trunk.endpoints[last_endpoint];
-	OSMO_ASSERT(endp->net_end.codec.payload_type == 0);
-	OSMO_ASSERT(endp->net_end.alt_codec.payload_type == 8);
+	OSMO_ASSERT(endp->net_end.codec.payload_type == 255);
+	OSMO_ASSERT(endp->net_end.alt_codec.payload_type == 0);
 
 	talloc_free(cfg);
 }