diff --git a/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/api/BlueMapAPIImpl.java b/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/api/BlueMapAPIImpl.java
index 00da738e..e702ba18 100644
--- a/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/api/BlueMapAPIImpl.java
+++ b/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/api/BlueMapAPIImpl.java
@@ -96,7 +96,7 @@ public Collection<BlueMapWorld> getWorlds() {
 
 	@Override
 	public String createImage(BufferedImage image, String path) throws IOException {
-		path = path.replaceAll("[^a-zA-Z_\\.\\-\\/]", "_");
+		path = path.replaceAll("[^a-zA-Z0-9_.\\-/]", "_");
 		String separator = FileSystems.getDefault().getSeparator();
 		
 		Path webRoot = plugin.getRenderConfig().getWebRoot().toPath().toAbsolutePath();
diff --git a/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/plugin/commands/Commands.java b/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/plugin/commands/Commands.java
index 7b916886..851ee753 100644
--- a/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/plugin/commands/Commands.java
+++ b/BlueMapCommon/src/main/java/de/bluecolored/bluemap/common/plugin/commands/Commands.java
@@ -60,10 +60,9 @@
 import de.bluecolored.bluemap.core.map.BmMap;
 import de.bluecolored.bluemap.core.map.MapRenderState;
 import de.bluecolored.bluemap.core.mca.ChunkAnvil112;
-import de.bluecolored.bluemap.core.mca.MCAChunk;
-import de.bluecolored.bluemap.core.mca.MCAWorld;
 import de.bluecolored.bluemap.core.resourcepack.ParseResourceException;
 import de.bluecolored.bluemap.core.world.Block;
+import de.bluecolored.bluemap.core.world.Chunk;
 import de.bluecolored.bluemap.core.world.World;
 
 import java.io.IOException;
@@ -529,23 +528,24 @@ public int debugBlockCommand(CommandContext<S> context) {
 		new Thread(() -> {
 			// collect and output debug info
 			Vector3i blockPos = position.floor().toInt();
-			Block block = new Block(world, blockPos.getX(), blockPos.getY(), blockPos.getZ());
-			Block blockBelow = new Block(null, 0, 0, 0).copy(block).add(0, -1, 0);
-			
+			Block block = world.getBlock(blockPos);
+			Block blockBelow = world.getBlock(blockPos.add(0, -1, 0));
+
 			String blockIdMeta = "";
 			String blockBelowIdMeta = "";
-			
-			if (world instanceof MCAWorld) {
-				MCAChunk chunk = ((MCAWorld) world).getChunkAtBlock(blockPos.getX(), blockPos.getY(), blockPos.getZ());
-				if (chunk instanceof ChunkAnvil112) {
-					blockIdMeta = " (" + ((ChunkAnvil112) chunk).getBlockIdMeta(blockPos) + ")";
-					blockBelowIdMeta = " (" + ((ChunkAnvil112) chunk).getBlockIdMeta(blockPos.add(0, -1, 0)) + ")";
-				}
+
+			Vector2i chunkPos = world.getChunkGrid().getCell(blockPos.toVector2(true));
+			Chunk chunk = world.getChunk(chunkPos.getX(), chunkPos.getY());
+
+			if (chunk instanceof ChunkAnvil112) {
+				blockIdMeta = " (" + ((ChunkAnvil112) chunk).getBlockIdMeta(blockPos) + ")";
+				blockBelowIdMeta = " (" + ((ChunkAnvil112) chunk).getBlockIdMeta(blockPos.add(0, -1, 0)) + ")";
 			}
 			
 			source.sendMessages(Arrays.asList(
 					Text.of(TextColor.GOLD, "Block at you: ", TextColor.WHITE, block, TextColor.GRAY, blockIdMeta),
-					Text.of(TextColor.GOLD, "Block below you: ", TextColor.WHITE, blockBelow, TextColor.GRAY, blockBelowIdMeta)
+					Text.of(TextColor.GOLD, "Block below you: ", TextColor.WHITE, blockBelow, TextColor.GRAY, blockBelowIdMeta),
+					Text.of(TextColor.GOLD, "Chunk: ", TextColor.WHITE, chunk)
 				));
 		}).start();
 		
@@ -749,13 +749,18 @@ public int updateCommand(CommandContext<S> context, boolean force) {
 				if (worldToRender != null) {
 					plugin.getServerInterface().persistWorldChanges(worldToRender.getUUID());
 					for (BmMap map : plugin.getMapTypes()) {
-						if (map.getWorld().equals(worldToRender)) maps.add(map);
+						if (map.getWorld().getUUID().equals(worldToRender.getUUID())) maps.add(map);
 					}
 				} else {
 					plugin.getServerInterface().persistWorldChanges(mapToRender.getWorld().getUUID());
 					maps.add(mapToRender);
 				}
 
+				if (maps.isEmpty()) {
+					source.sendMessage(Text.of(TextColor.RED, "No map has been found for this world that could be updated!"));
+					return;
+				}
+
 				for (BmMap map : maps) {
 					MapUpdateTask updateTask = new MapUpdateTask(map, center, radius);
 					plugin.getRenderManager().scheduleRenderTask(updateTask);
diff --git a/BlueMapCore/src/main/java/de/bluecolored/bluemap/core/mca/MCAChunk.java b/BlueMapCore/src/main/java/de/bluecolored/bluemap/core/mca/MCAChunk.java
index d0c05ee4..4752bae7 100644
--- a/BlueMapCore/src/main/java/de/bluecolored/bluemap/core/mca/MCAChunk.java
+++ b/BlueMapCore/src/main/java/de/bluecolored/bluemap/core/mca/MCAChunk.java
@@ -84,4 +84,12 @@ public static MCAChunk empty() {
 		return EmptyChunk.INSTANCE;
 	}
 
+	@Override
+	public String toString() {
+		return "MCAChunk{" +
+			   "dataVersion=" + dataVersion +
+			   "isGenerated()=" + isGenerated() +
+			   '}';
+	}
+
 }