diff --git a/src/pocketmine/network/mcpe/protocol/StartGamePacket.php b/src/pocketmine/network/mcpe/protocol/StartGamePacket.php
index 64084152c..fb32c4f0c 100644
--- a/src/pocketmine/network/mcpe/protocol/StartGamePacket.php
+++ b/src/pocketmine/network/mcpe/protocol/StartGamePacket.php
@@ -211,7 +211,11 @@ class StartGamePacket extends DataPacket{
 
 		$this->enchantmentSeed = $this->getVarInt();
 
-		$this->blockTable = (new NetworkLittleEndianNBTStream())->read($this->buffer, false, $this->offset, 512);
+		$blockTable = (new NetworkLittleEndianNBTStream())->read($this->buffer, false, $this->offset, 512);
+		if(!($blockTable instanceof ListTag)){
+			throw new \UnexpectedValueException("Wrong block table root NBT tag type");
+		}
+		$this->blockTable = $blockTable;
 
 		$this->itemTable = [];
 		for($i = 0, $count = $this->getUnsignedVarInt(); $i < $count; ++$i){