Turns out the Yaz0 is big endian

yes, even with SM3DAS

BMGEditor/FS/Yaz0Stream.cs

@@ -6,7 +6,7 @@ using System.IO;
 
 namespace BMGEditor
 {
-    public class Yaz0Stream : MemoryStream //ONLY WORKS WITH BIG ENDIAN - TO REWRITE !!
+    public class Yaz0Stream : MemoryStream 
     {
         public Yaz0Stream(Stream backend)
             : base(1)

BMGEditor/Program.cs

@@ -8,8 +8,8 @@ namespace BMGEditor
     public static class Variables
     {
         public const string softwareName = "Luma";
-        public const string softwareVersion = "v1.1";
-        public const UInt64 build = 2;
+        public const string softwareVersion = "build 3";
+        public const UInt64 build = 3;
         public const bool isBeta = true;
     }