diff --git a/src/main/java/com/falsepattern/lib/asm/ASMUtil.java b/src/main/java/com/falsepattern/lib/asm/ASMUtil.java
index 71f2131..6356d36 100644
--- a/src/main/java/com/falsepattern/lib/asm/ASMUtil.java
+++ b/src/main/java/com/falsepattern/lib/asm/ASMUtil.java
@@ -181,6 +181,7 @@ public class ASMUtil {
     @StableAPI.Expose
     public static byte[] serializeClass(ClassNode cn, int writerFlags) {
         val writer = new ClassWriter(writerFlags);
+        cn.accept(writer);
         return writer.toByteArray();
     }
 
diff --git a/src/main/java/com/falsepattern/lib/internal/asm/IMixinPluginTransformer.java b/src/main/java/com/falsepattern/lib/internal/asm/IMixinPluginTransformer.java
index b424867..d31a10c 100644
--- a/src/main/java/com/falsepattern/lib/internal/asm/IMixinPluginTransformer.java
+++ b/src/main/java/com/falsepattern/lib/internal/asm/IMixinPluginTransformer.java
@@ -26,9 +26,6 @@ import com.falsepattern.lib.internal.Tags;
 import com.falsepattern.lib.mixin.MixinInfo;
 import lombok.val;
 import org.objectweb.asm.tree.ClassNode;
-import org.objectweb.asm.tree.MethodNode;
-
-import java.util.ArrayList;
 
 public class IMixinPluginTransformer implements IClassNodeTransformer {
     @Override
@@ -44,26 +41,16 @@ public class IMixinPluginTransformer implements IClassNodeTransformer {
     @Override
     public void transform(ClassNode cn, String transformedName, boolean obfuscated) {
         val methods = cn.methods;
-        val remove = new ArrayList<MethodNode>();
-        if (MixinInfo.isMixinBooterLegacy()) {
-            FPTransformer.LOG.info("Detected MixinBooterLegacy. Selecting proper methods in IMixinPlugin.");
-            for (val method : methods) {
-                if (method.name.equals("preApply_obsolete") || method.name.equals("postApply_obsolete")) {
-                    remove.add(method);
-                }
-            }
-            methods.removeAll(remove);
-        } else {
-            FPTransformer.LOG.info("Could not detect MixinBooterLegacy. Selecting proper methods in IMixinPlugin.");
+        if (!MixinInfo.isMixinBooterLegacy()) {
+            FPTransformer.LOG.info("Could not detect MixinBooterLegacy. Converting IMixinPlugin to legacy compat mode.");
             for (val method : methods) {
                 if (method.name.equals("preApply") || method.name.equals("postApply")) {
-                    remove.add(method);
-                }
-            }
-            methods.removeAll(remove);
-            for (val method : methods) {
-                if (method.name.equals("preApply_obsolete") || method.name.equals("postApply_obsolete")) {
-                    method.name = method.name.substring(0, method.name.indexOf('_'));
+                    method.desc = method.desc.replace("org/spongepowered/libraries/org/objectweb/asm/tree/ClassNode",
+                                                      "org/spongepowered/asm/lib/tree/ClassNode");
+                    for (val local: method.localVariables) {
+                        local.desc = local.desc.replace("org/spongepowered/libraries/org/objectweb/asm/tree/ClassNode",
+                                                        "org/spongepowered/asm/lib/tree/ClassNode");
+                    }
                 }
             }
         }
diff --git a/src/main/java/com/falsepattern/lib/mixin/IMixinPlugin.java b/src/main/java/com/falsepattern/lib/mixin/IMixinPlugin.java
index d39e9a6..ea3e990 100644
--- a/src/main/java/com/falsepattern/lib/mixin/IMixinPlugin.java
+++ b/src/main/java/com/falsepattern/lib/mixin/IMixinPlugin.java
@@ -25,9 +25,9 @@ import com.falsepattern.lib.util.FileUtil;
 import lombok.val;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.spongepowered.asm.lib.tree.ClassNode;
 import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
 import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
+import org.spongepowered.libraries.org.objectweb.asm.tree.ClassNode;
 
 import net.minecraft.launchwrapper.Launch;
 
@@ -146,37 +146,15 @@ public interface IMixinPlugin extends IMixinConfigPlugin {
         return success;
     }
 
-    /**
-     * Fallback for spongemixins. Removed for mixinbooter
-     */
-    @StableAPI.Expose(since = "__INTERNAL__")
-    default void preApply_obsolete(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
-
-    }
-
-    /**
-     * Fallback for spongemixins. Removed for mixinbooter
-     */
-    @StableAPI.Expose(since = "__INTERNAL__")
-    default void postApply_obsolete(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
-
-    }
-
-    /**
-     * Regular behaviour for mixinbooter. Removed for spongemixins
-     */
     @Override
     @StableAPI.Expose(since = "__INTERNAL__")
-    default void preApply(String targetClassName, org.spongepowered.libraries.org.objectweb.asm.tree.ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+    default void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
 
     }
 
-    /**
-     * Regular behaviour for mixinbooter. Removed for spongemixins
-     */
     @Override
     @StableAPI.Expose(since = "__INTERNAL__")
-    default void postApply(String targetClassName, org.spongepowered.libraries.org.objectweb.asm.tree.ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+    default void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
 
     }
 }