diff --git a/core/src/main/java/com/volmit/iris/core/IrisSettings.java b/core/src/main/java/com/volmit/iris/core/IrisSettings.java
index 65991a686..212b1551f 100644
--- a/core/src/main/java/com/volmit/iris/core/IrisSettings.java
+++ b/core/src/main/java/com/volmit/iris/core/IrisSettings.java
@@ -244,6 +244,7 @@ public class IrisSettings {
         public boolean preventLeafDecay = true;
         public boolean useMulticore = false;
         public boolean offsetNoiseTypes = false;
+        public boolean earlyCustomBlocks = false;
     }
 
     @Data
diff --git a/core/src/main/java/com/volmit/iris/engine/IrisWorldManager.java b/core/src/main/java/com/volmit/iris/engine/IrisWorldManager.java
index e44ac8700..1edfee1f1 100644
--- a/core/src/main/java/com/volmit/iris/engine/IrisWorldManager.java
+++ b/core/src/main/java/com/volmit/iris/engine/IrisWorldManager.java
@@ -20,7 +20,9 @@ package com.volmit.iris.engine;
 
 import com.volmit.iris.Iris;
 import com.volmit.iris.core.IrisSettings;
+import com.volmit.iris.core.link.Identifier;
 import com.volmit.iris.core.loader.IrisData;
+import com.volmit.iris.core.service.ExternalDataSVC;
 import com.volmit.iris.engine.framework.Engine;
 import com.volmit.iris.engine.framework.EngineAssignedWorldManager;
 import com.volmit.iris.engine.object.*;
@@ -424,18 +426,35 @@ public class IrisWorldManager extends EngineAssignedWorldManager {
         }
 
         var ref = new WeakReference<>(e.getWorld());
-        int x = e.getX(), z = e.getZ();
+        int cX = e.getX(), cZ = e.getZ();
         J.s(() -> {
             World world = ref.get();
-            if (world == null || !world.isChunkLoaded(x, z))
+            if (world == null || !world.isChunkLoaded(cX, cZ))
                 return;
             energy += 0.3;
             fixEnergy();
-            getEngine().cleanupMantleChunk(x, z);
+            getEngine().cleanupMantleChunk(cX, cZ);
         }, IrisSettings.get().getPerformance().mantleCleanupDelay);
 
         if (generated) {
             //INMS.get().injectBiomesFromMantle(e, getMantle());
+
+            if (!IrisSettings.get().getGenerator().earlyCustomBlocks) return;
+            e.addPluginChunkTicket(Iris.instance);
+            J.s(() -> {
+                var chunk = getMantle().getChunk(e).use();
+                int minY = getTarget().getWorld().minHeight();
+                try {
+                    chunk.raiseFlagUnchecked(MantleFlag.CUSTOM, () -> {
+                        chunk.iterate(Identifier.class, (x, y, z, v) -> {
+                            Iris.service(ExternalDataSVC.class).processUpdate(getEngine(), e.getBlock(x & 15, y + minY, z & 15), v);
+                        });
+                    });
+                } finally {
+                    chunk.release();
+                    e.removePluginChunkTicket(Iris.instance);
+                }
+            }, RNG.r.i(20, 60));
         }
     }
 
diff --git a/core/src/main/java/com/volmit/iris/engine/framework/Engine.java b/core/src/main/java/com/volmit/iris/engine/framework/Engine.java
index 9026729e9..e6ac9f954 100644
--- a/core/src/main/java/com/volmit/iris/engine/framework/Engine.java
+++ b/core/src/main/java/com/volmit/iris/engine/framework/Engine.java
@@ -296,20 +296,20 @@ public interface Engine extends DataProvider, Fallible, LootProvider, BlockUpdat
         try {
             Semaphore semaphore = new Semaphore(3);
             chunk.raiseFlag(MantleFlag.ETCHED, () -> {
-                chunk.raiseFlag(MantleFlag.TILE, run(semaphore, () -> {
+                chunk.raiseFlagUnchecked(MantleFlag.TILE, run(semaphore, () -> {
                     chunk.iterate(TileWrapper.class, (x, y, z, v) -> {
                         Block block = c.getBlock(x & 15, y + getWorld().minHeight(), z & 15);
                         if (!TileData.setTileState(block, v.getData()))
                             Iris.warn("Failed to set tile entity data at [%d %d %d | %s] for tile %s!", block.getX(), block.getY(), block.getZ(), block.getType().getKey(), v.getData().getMaterial().getKey());
                     });
                 }, 0));
-                chunk.raiseFlag(MantleFlag.CUSTOM, run(semaphore, () -> {
+                chunk.raiseFlagUnchecked(MantleFlag.CUSTOM, run(semaphore, () -> {
                     chunk.iterate(Identifier.class, (x, y, z, v) -> {
                         Iris.service(ExternalDataSVC.class).processUpdate(this, c.getBlock(x & 15, y + getWorld().minHeight(), z & 15), v);
                     });
                 }, 0));
 
-                chunk.raiseFlag(MantleFlag.UPDATE, run(semaphore, () -> {
+                chunk.raiseFlagUnchecked(MantleFlag.UPDATE, run(semaphore, () -> {
                     PrecisionStopwatch p = PrecisionStopwatch.start();
                     int[][] grid = new int[16][16];
                     for (int x = 0; x < 16; x++) {
diff --git a/core/src/main/java/com/volmit/iris/util/mantle/MantleChunk.java b/core/src/main/java/com/volmit/iris/util/mantle/MantleChunk.java
index 7208b6fb9..f7cf935cc 100644
--- a/core/src/main/java/com/volmit/iris/util/mantle/MantleChunk.java
+++ b/core/src/main/java/com/volmit/iris/util/mantle/MantleChunk.java
@@ -181,6 +181,11 @@ public class MantleChunk {
         }
     }
 
+    public void raiseFlagUnchecked(MantleFlag flag, Runnable r) {
+        if (closed.get()) throw new IllegalStateException("Chunk is closed!");
+        if (flags.compareAndSet(flag.ordinal(), false, true)) r.run();
+    }
+
     public boolean isFlagged(MantleFlag flag) {
         return flags.get(flag.ordinal());
     }