diff --git a/src/network/mcpe/convert/ItemTranslator.php b/src/network/mcpe/convert/ItemTranslator.php
index d1a7c3a58..1af9adba2 100644
--- a/src/network/mcpe/convert/ItemTranslator.php
+++ b/src/network/mcpe/convert/ItemTranslator.php
@@ -142,10 +142,10 @@ final class ItemTranslator{
 	}
 
 	/**
-	 * @return int[]
-	 * @phpstan-return array{int, int}
+	 * @return int[]|null
+	 * @phpstan-return array{int, int}|null
 	 */
-	public function toNetworkId(int $internalId, int $internalMeta) : array{
+	public function toNetworkIdQuiet(int $internalId, int $internalMeta) : ?array{
 		if($internalMeta === -1){
 			$internalMeta = 0x7fff;
 		}
@@ -156,7 +156,16 @@ final class ItemTranslator{
 			return [$this->simpleCoreToNetMapping[$internalId], $internalMeta];
 		}
 
-		throw new \InvalidArgumentException("Unmapped ID/metadata combination $internalId:$internalMeta");
+		return null;
+	}
+
+	/**
+	 * @return int[]
+	 * @phpstan-return array{int, int}
+	 */
+	public function toNetworkId(int $internalId, int $internalMeta) : array{
+		return $this->toNetworkIdQuiet($internalId, $internalMeta) ??
+			throw new \InvalidArgumentException("Unmapped ID/metadata combination $internalId:$internalMeta");
 	}
 
 	/**
diff --git a/src/network/mcpe/convert/TypeConverter.php b/src/network/mcpe/convert/TypeConverter.php
index d878423f6..21b3ab749 100644
--- a/src/network/mcpe/convert/TypeConverter.php
+++ b/src/network/mcpe/convert/TypeConverter.php
@@ -58,6 +58,7 @@ class TypeConverter{
 
 	private const DAMAGE_TAG = "Damage"; //TAG_Int
 	private const DAMAGE_TAG_CONFLICT_RESOLUTION = "___Damage_ProtocolCollisionResolution___";
+	private const PM_ID_TAG = "___Id___";
 	private const PM_META_TAG = "___Meta___";
 
 	/** @var int */
@@ -143,26 +144,40 @@ class TypeConverter{
 		}
 
 		$isBlockItem = $itemStack->getId() < 256;
-		if($itemStack instanceof Durable and $itemStack->getDamage() > 0){
-			if($nbt !== null){
-				if(($existing = $nbt->getTag(self::DAMAGE_TAG)) !== null){
-					$nbt->removeTag(self::DAMAGE_TAG);
-					$nbt->setTag(self::DAMAGE_TAG_CONFLICT_RESOLUTION, $existing);
-				}
-			}else{
-				$nbt = new CompoundTag();
-			}
-			$nbt->setInt(self::DAMAGE_TAG, $itemStack->getDamage());
-		}elseif($isBlockItem && $itemStack->getMeta() !== 0){
-			//TODO HACK: This foul-smelling code ensures that we can correctly deserialize an item when the
-			//client sends it back to us, because as of 1.16.220, blockitems quietly discard their metadata
-			//client-side. Aside from being very annoying, this also breaks various server-side behaviours.
+
+		$idMeta = ItemTranslator::getInstance()->toNetworkIdQuiet($itemStack->getId(), $itemStack->getMeta());
+		if($idMeta === null){
+			//Display unmapped items as INFO_UPDATE, but stick something in their NBT to make sure they don't stack with
+			//other unmapped items.
+			[$id, $meta] = ItemTranslator::getInstance()->toNetworkId(ItemIds::INFO_UPDATE, 0);
 			if($nbt === null){
 				$nbt = new CompoundTag();
 			}
+			$nbt->setInt(self::PM_ID_TAG, $itemStack->getId());
 			$nbt->setInt(self::PM_META_TAG, $itemStack->getMeta());
+		}else{
+			[$id, $meta] = $idMeta;
+
+			if($itemStack instanceof Durable and $itemStack->getDamage() > 0){
+				if($nbt !== null){
+					if(($existing = $nbt->getTag(self::DAMAGE_TAG)) !== null){
+						$nbt->removeTag(self::DAMAGE_TAG);
+						$nbt->setTag(self::DAMAGE_TAG_CONFLICT_RESOLUTION, $existing);
+					}
+				}else{
+					$nbt = new CompoundTag();
+				}
+				$nbt->setInt(self::DAMAGE_TAG, $itemStack->getDamage());
+			}elseif($isBlockItem && $itemStack->getMeta() !== 0){
+				//TODO HACK: This foul-smelling code ensures that we can correctly deserialize an item when the
+				//client sends it back to us, because as of 1.16.220, blockitems quietly discard their metadata
+				//client-side. Aside from being very annoying, this also breaks various server-side behaviours.
+				if($nbt === null){
+					$nbt = new CompoundTag();
+				}
+				$nbt->setInt(self::PM_META_TAG, $itemStack->getMeta());
+			}
 		}
-		[$id, $meta] = ItemTranslator::getInstance()->toNetworkId($itemStack->getId(), $itemStack->getMeta());
 
 		$blockRuntimeId = 0;
 		if($isBlockItem){
@@ -197,6 +212,13 @@ class TypeConverter{
 
 		if($compound !== null){
 			$compound = clone $compound;
+			if(($idTag = $compound->getTag(self::PM_ID_TAG)) instanceof IntTag){
+				$id = $idTag->getValue();
+				$compound->removeTag(self::PM_ID_TAG);
+				if($compound->count() === 0){
+					$compound = null;
+				}
+			}
 			if(($damageTag = $compound->getTag(self::DAMAGE_TAG)) instanceof IntTag){
 				$meta = $damageTag->getValue();
 				$compound->removeTag(self::DAMAGE_TAG);