diff --git a/src/network/mcpe/serializer/ChunkSerializer.php b/src/network/mcpe/serializer/ChunkSerializer.php
index e1e010d65..2b1643ac0 100644
--- a/src/network/mcpe/serializer/ChunkSerializer.php
+++ b/src/network/mcpe/serializer/ChunkSerializer.php
@@ -63,9 +63,13 @@ final class ChunkSerializer{
 				$stream->putByte(($blocks->getBitsPerBlock() << 1) | 1); //last 1-bit means "network format", but seems pointless
 				$stream->put($blocks->getWordArray());
 				$palette = $blocks->getPalette();
-				$stream->putVarInt(count($palette)); //yes, this is intentionally zigzag
+
+				//these LSHIFT by 1 uvarints are optimizations: the client expects zigzag varints here
+				//but since we know they are always unsigned, we can avoid the extra fcall overhead of
+				//zigzag and just shift directly.
+				$stream->putUnsignedVarInt(count($palette) << 1); //yes, this is intentionally zigzag
 				foreach($palette as $p){
-					$stream->putVarInt(RuntimeBlockMapping::toStaticRuntimeId($p >> 4, $p & 0xf));
+					$stream->putUnsignedVarInt(RuntimeBlockMapping::toStaticRuntimeId($p >> 4, $p & 0xf) << 1);
 				}
 			}
 		}