Index: core/src/test/java/quickfix/mina/message/FIXMessageDecoderTest.java
===================================================================
--- core/src/test/java/quickfix/mina/message/FIXMessageDecoderTest.java	(.../vendor-1.5.0)	(revision 52)
+++ core/src/test/java/quickfix/mina/message/FIXMessageDecoderTest.java	(.../IG-1.5.0)	(revision 61)
@@ -137,7 +137,20 @@
         assertEquals("wrong result", MessageDecoderResult.NEED_DATA, decoder
                 .decodable(null, buffer));
     }
-
+    @Test 
+    public void testPartialHeader2() throws Exception {
+        setUpBuffer("8=FIX.4.2\0019");
+        assertEquals("wrong result", MessageDecoderResult.NEED_DATA, decoder
+                .decodable(null, buffer));
+    }
+    
+    @Test 
+    public void testPartialHeaderFixt() throws Exception {
+        setUpBuffer("8=FIXT.1.1\0019");
+        assertEquals("wrong result", MessageDecoderResult.NEED_DATA, decoder
+                .decodable(null, buffer));
+    }
+    
     // QFJ-376
     @Test
     public void testGarbageData() throws Exception {
@@ -157,18 +170,24 @@
     public void testSplitMessage() throws Exception {
         String data = "8=FIX.4.2\0019=12\00135=X\001108=30\00110=049\001";
         for (int i = 1; i < data.length(); i++) {
-            doSplitMessageTest(i, data);
+            doSplitMessageTest(i, data,12);
         }
     }
-
-    private void doSplitMessageTest(int splitOffset, String data) throws ProtocolCodecException {
+    @Test 
+    public void testSplitMessageFixt() throws Exception {
+        String data = "8=FIXT.1.1\0019=12\00135=X\001108=30\00110=049\001";
+        for (int i = 1; i < data.length(); i++) {
+            doSplitMessageTest(i, data,13);
+        }
+    }
+    private void doSplitMessageTest(int splitOffset, String data, int headerSize) throws ProtocolCodecException {
         String firstChunk = data.substring(0, splitOffset);
         String remaining = data.substring(splitOffset);
         buffer.put(firstChunk.getBytes());
         buffer.flip();
         decoderOutput.reset();
 
-        if (splitOffset < 12) {
+        if (splitOffset < headerSize) {
             assertEquals("shouldn't recognize header; offset=" + splitOffset,
                     MessageDecoderResult.NEED_DATA, decoder.decodable(null, buffer));
         } else {
@@ -327,7 +346,22 @@
 
     @Test 
     public void testMinaDemux() throws Exception {
-        DemuxingProtocolCodecFactory codecFactory = new DemuxingProtocolCodecFactory();
+        String message = "8=FIX.4.2\0019=12\00135=X\001108=30\00110=036\001";
+        
+        doTestMinaDemux(message);
+
+    }
+
+    @Test 
+    public void testMinaDemuxFixt() throws Exception {
+        String message = "8=FIXT.1.1\0019=12\00135=X\001108=30\00110=036\001";
+        
+        doTestMinaDemux(message);
+
+    }
+    
+   private void doTestMinaDemux(String message) throws Exception, UnsupportedEncodingException {
+      DemuxingProtocolCodecFactory codecFactory = new DemuxingProtocolCodecFactory();
         codecFactory.register(FIXMessageDecoder.class);
 
         ProtocolDecoder decoder = codecFactory.getDecoder();
@@ -338,7 +372,7 @@
         int count = 5;
         String data = "";
         for (int i = 0; i < count; i++) {
-            data += "8=FIX.4.2\0019=12\00135=X\001108=30\00110=036\001";
+            data += message;
         }
 
         for (int i = 1; i < data.length(); i++) {
@@ -358,9 +392,8 @@
             output.reset();
             buffer.clear();
         }
+   }
 
-    }
-
     private void assertMessageFound(String data) throws ProtocolCodecException {
         assertMessageFound(data, 1);
     }
Index: core/src/main/java/quickfix/mina/message/FIXMessageDecoder.java
===================================================================
--- core/src/main/java/quickfix/mina/message/FIXMessageDecoder.java	(.../vendor-1.5.0)	(revision 52)
+++ core/src/main/java/quickfix/mina/message/FIXMessageDecoder.java	(.../IG-1.5.0)	(revision 61)
@@ -123,7 +123,7 @@
         }
         if (messageCount > 0) {
             // Mina will compact the buffer because we can't detect a header
-            if (in.remaining() < minMaskLength(HEADER_PATTERN)) {
+            if (state == SEEKING_HEADER) {
                 position = 0;
             }
             return MessageDecoderResult.OK;
@@ -337,6 +337,10 @@
                 return -1;
             }
         }
+        if(dataOffset != data.length){
+           // when minMaskLength(data) != data.length we might run out of buffer before we run out of data
+           return -1;
+        }
         return bufferOffset - initOffset;
     }