diff --git a/Log/MavlinkLog.cs b/Log/MavlinkLog.cs
index 9b566ba916..9df9e563b4 100644
--- a/Log/MavlinkLog.cs
+++ b/Log/MavlinkLog.cs
@@ -744,9 +744,20 @@ private void BUT_graphmavlog_Click(object sender, EventArgs e)
             0x600000,0x006000,0x000060,0x606000,0x600060,0x006060,  
             0xA00000,0x00A000,0x0000A0,0xA0A000,0xA000A0,0x00A0A0, 
             0xE00000,0x00E000,0x0000E0,0xE0E000,0xE000E0,0x00E0E0,  */
-        };
-
-        // Form selectform;
+        };
+
+        // Form selectform;
+
+        private static string ReplaceLastOccurrence(string Source, string Find, string Replace)
+        {
+            int place = Source.LastIndexOf(Find);
+
+            if (place == -1)
+                return Source;
+
+            string result = Source.Remove(place, Find.Length).Insert(place, Replace);
+            return result;
+        }
 
         private List<string> GetLogFileValidFields(string logfile)
         {
@@ -827,7 +838,8 @@ private List<string> GetLogFileValidFields(string logfile)
 
                     if (true)
                     {
-                        string packetname = test.Name.Replace("mavlink_", "").Replace("_t", "").ToUpper();
+                        string packetname = ReplaceLastOccurrence(test.Name, "_t", "");
+                        packetname = packetname.Replace("mavlink_", "").ToUpper();
 
                         if (!packetdata.ContainsKey(packetname))
                         {
@@ -1206,7 +1218,8 @@ private void ResetTreeView(List<string> seenmessagetypes)
             {
                 var items = item.Split('.');
 
-                var item1text = items[0].Replace("mavlink_", "").Replace("_t", "").ToUpper();
+                var item1text = ReplaceLastOccurrence(items[0], "_t", "");
+                item1text = item1text.Replace("mavlink_", "").ToUpper();
                 var item2text = items[1];
 
                 if (!addedrootnodes.ContainsKey(item1text))