diff --git a/vtm/src/org/oscim/renderer/BufferObject.java b/vtm/src/org/oscim/renderer/BufferObject.java
index 79ab51f0..89e8b0ff 100644
--- a/vtm/src/org/oscim/renderer/BufferObject.java
+++ b/vtm/src/org/oscim/renderer/BufferObject.java
@@ -17,6 +17,8 @@ package org.oscim.renderer;
 
 import java.nio.Buffer;
 
+import javax.annotation.CheckReturnValue;
+
 import org.oscim.backend.GL20;
 import org.oscim.backend.Log;
 
@@ -125,9 +127,10 @@ public final class BufferObject {
 		return bo;
 	}
 
-	public static synchronized void release(BufferObject bo) {
+	@CheckReturnValue
+	public static synchronized BufferObject release(BufferObject bo) {
 		if (bo == null)
-			return;
+			return null;
 
 		// if (counter > 200) {
 		// Log.d(TAG, "should clear some buffers " + counter);
@@ -137,6 +140,8 @@ public final class BufferObject {
 		bo.next = pool[t];
 		pool[t] = bo;
 		counter[t]++;
+
+		return null;
 	}
 
 	// Note: only call from GL-Thread
diff --git a/vtm/src/org/oscim/renderer/ElementRenderer.java b/vtm/src/org/oscim/renderer/ElementRenderer.java
index cf5f1e7d..9279d4f7 100644
--- a/vtm/src/org/oscim/renderer/ElementRenderer.java
+++ b/vtm/src/org/oscim/renderer/ElementRenderer.java
@@ -139,8 +139,7 @@ public abstract class ElementRenderer extends LayerRenderer {
 		int newSize = layers.getSize();
 
 		if (newSize <= 0) {
-			BufferObject.release(layers.vbo);
-			layers.vbo = null;
+			layers.vbo = BufferObject.release(layers.vbo);
 			setReady(false);
 			return;
 		}
diff --git a/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java b/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java
index 8dc65d39..a6a20d52 100644
--- a/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java
+++ b/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java
@@ -416,10 +416,8 @@ public class ExtrusionLayer extends RenderElement {
 	@Override
 	protected void clear() {
 		if (compiled) {
-			BufferObject.release(vboIndices);
-			BufferObject.release(vboVertices);
-			vboIndices = null;
-			vboVertices = null;
+			vboIndices = BufferObject.release(vboIndices);
+			vboVertices = BufferObject.release(vboVertices);
 		} else {
 			for (int i = 0; i < 4; i++)
 				VertexItem.pool.releaseAll(mIndices[i]);
diff --git a/vtm/src/org/oscim/renderer/elements/MeshLayer.java b/vtm/src/org/oscim/renderer/elements/MeshLayer.java
index d67d8bd3..52b523b7 100644
--- a/vtm/src/org/oscim/renderer/elements/MeshLayer.java
+++ b/vtm/src/org/oscim/renderer/elements/MeshLayer.java
@@ -43,6 +43,10 @@ public class MeshLayer extends RenderElement {
 	}
 
 	public void addMesh(GeometryBuffer geom) {
+		if (geom.index[0] < 6) {
+			Log.d(TAG, "invalid poly");
+			return;
+		}
 		if (vertexItems == null) {
 			vertexItems = VertexItem.pool.get();
 			indiceItems = VertexItem.pool.get();
@@ -69,9 +73,10 @@ public class MeshLayer extends RenderElement {
 	@Override
 	protected void compile(ShortBuffer sbuf) {
 		if (indiceItems == null) {
-
+			indicesVbo = BufferObject.release(indicesVbo);
 			return;
 		}
+
 		Log.d(TAG, "compile");
 		// add vertices to shared VBO
 		ElementLayers.addPoolItems(this, sbuf);
@@ -95,19 +100,20 @@ public class MeshLayer extends RenderElement {
 
 		sbuf.flip();
 
-		indicesVbo = BufferObject.get(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
+		if (indicesVbo == null)
+			indicesVbo = BufferObject.get(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
+
 		indicesVbo.loadBufferData(sbuf, sbuf.limit() * 2);
 	}
 
 	@Override
 	protected void clear() {
-		BufferObject.release(indicesVbo);
+		indicesVbo = BufferObject.release(indicesVbo);
 		VertexItem.pool.releaseAll(indiceItems);
 		VertexItem.pool.releaseAll(vertexItems);
 
 		indiceItems = null;
 		vertexItems = null;
-		indicesVbo = null;
 	}
 
 	public static class Renderer {
@@ -147,6 +153,9 @@ public class MeshLayer extends RenderElement {
 			for (; l != null && l.type == RenderElement.MESH; l = l.next) {
 				MeshLayer ml = (MeshLayer) l;
 
+				if (ml.indicesVbo == null)
+					continue;
+
 				ml.indicesVbo.bind();
 
 				GL.glVertexAttribPointer(hVertexPosition, 2, GL20.GL_SHORT,
diff --git a/vtm/src/org/oscim/tiling/MapTile.java b/vtm/src/org/oscim/tiling/MapTile.java
index eca2b434..efbe6ceb 100644
--- a/vtm/src/org/oscim/tiling/MapTile.java
+++ b/vtm/src/org/oscim/tiling/MapTile.java
@@ -223,11 +223,7 @@ public class MapTile extends Tile {
 	protected void clear() {
 		if (layers != null) {
 			// TODO move this to layers clear
-			if (layers.vbo != null) {
-				BufferObject.release(layers.vbo);
-				layers.vbo = null;
-			}
-
+			layers.vbo = BufferObject.release(layers.vbo);
 			layers.clear();
 		}
 
diff --git a/vtm/src/org/oscim/tiling/TileRenderer.java b/vtm/src/org/oscim/tiling/TileRenderer.java
index efeac387..2df7409b 100644
--- a/vtm/src/org/oscim/tiling/TileRenderer.java
+++ b/vtm/src/org/oscim/tiling/TileRenderer.java
@@ -173,8 +173,7 @@ public class TileRenderer extends LayerRenderer {
 			if (!ElementRenderer.uploadLayers(tile.layers, newSize, true)) {
 				Log.d(TAG, "BUG uploadTileData " + tile + " failed!");
 
-				BufferObject.release(tile.layers.vbo);
-				tile.layers.vbo = null;
+				tile.layers.vbo = BufferObject.release(tile.layers.vbo);
 				tile.layers.clear();
 				tile.layers = null;
 				return 0;