diff --git a/spine-unity/Assets/Spine/Runtime/spine-unity/Asset Types/SkeletonDataCompatibility.cs b/spine-unity/Assets/Spine/Runtime/spine-unity/Asset Types/SkeletonDataCompatibility.cs
index 4eaf95062..97b18e9d5 100644
--- a/spine-unity/Assets/Spine/Runtime/spine-unity/Asset Types/SkeletonDataCompatibility.cs	
+++ b/spine-unity/Assets/Spine/Runtime/spine-unity/Asset Types/SkeletonDataCompatibility.cs	
@@ -170,21 +170,13 @@ namespace Spine.Unity {
 			string fileText = file.text;
 			const int maxCharsToCheck = 256;
 			int numCharsToCheck = Math.Min(fileText.Length, maxCharsToCheck);
-			if (fileText.IndexOf("\"skeleton\"", 0, numCharsToCheck) != -1 ||
-				fileText.IndexOf("\"hash\"", 0, numCharsToCheck) != -1 ||
-				fileText.IndexOf("\"spine\"", 0, numCharsToCheck) != -1)
-				return true;
-
-			int jsonCharCount = 0;
-			const string jsonChars = "{}:\",";
 			for (int i = 0; i < numCharsToCheck; ++i) {
 				char c = fileText[i];
-				if (jsonChars.IndexOf(c) != -1 || char.IsWhiteSpace(c))
-					++jsonCharCount;
+				if (char.IsWhiteSpace(c))
+					continue;
+				return c == '{';
 			}
-			if (jsonCharCount > numCharsToCheck / 10)
-				return true;
-			return false;
+			return true;
 		}
 
 		public static CompatibilityProblemInfo GetCompatibilityProblemInfo (VersionInfo fileVersion) {
diff --git a/spine-xna/example-content/SpineEffectNormalmap.fx b/spine-xna/example-content/SpineEffectNormalmap.fx
index ff86b8bcb..365ef76ee 100644
--- a/spine-xna/example-content/SpineEffectNormalmap.fx
+++ b/spine-xna/example-content/SpineEffectNormalmap.fx
@@ -47,6 +47,7 @@ void GetLightContributionBlinnPhong(inout float3 diffuseResult, inout float3 spe
 	diffuseResult += lightDiffuse * max(0.0, dot(normal, -lightDirection));
 	half3 halfVector = normalize(-lightDirection + viewDirection);
 	float nDotH = max(0, dot(normal, halfVector));
+	specularExponent = max(0.00001, specularExponent); // prevent fx compiler error at pow() below
 	specularResult += lightSpecular * pow(nDotH, specularExponent);
 }