MTP3MG: fixe parse/encode ordering if H0/H1 nibbles
diff --git a/src/mtp3_codec.erl b/src/mtp3_codec.erl
index cbb9052..9dc50c2 100644
--- a/src/mtp3_codec.erl
+++ b/src/mtp3_codec.erl
@@ -58,19 +58,19 @@
 
 
 decode_payload(?MTP3_SERV_MTN, Payload) ->
-	<<H0:4, H1:4, _:4, Len:4, TP/binary>> = Payload,
+	<<H1:4, H0:4, Len:4, 0:4, TP/binary>> = Payload,
 	#mtp3mg_msg{h0 = H0, h1 = H1, payload = TP};
 decode_payload(?MTP3_SERV_MGMT, Payload) ->
-	<<H0:4, H1:4, Remain/binary>> = Payload,
+	<<H1:4, H0:4, Remain/binary>> = Payload,
 	#mtp3mg_msg{h0 = H0, h1 = H1, payload = Payload};
 decode_payload(_, Payload) ->
 	Payload.
 
 payload_to_binary(?MTP3_SERV_MTN, #mtp3mg_msg{h0=H0, h1=H1, payload=TP}) ->
 	Len = byte_size(TP),
-	<<H0:4, H1:4, 0:4, Len:4, TP/binary>>;
+	<<H1:4, H0:4, Len:4, 0:4, TP/binary>>;
 payload_to_binary(?MTP3_SERV_MGMT, #mtp3mg_msg{h0=H0, h1=H1, payload=Payload}) ->
-	<<H0:4, H1:4, Payload/binary>>;
+	<<H1:4, H0:4, Payload/binary>>;
 payload_to_binary(_, Whatever) ->
 	Whatever.