diff --git a/src/Formats.c b/src/Formats.c
index b9275383c..d4ccd2e2f 100644
--- a/src/Formats.c
+++ b/src/Formats.c
@@ -421,6 +421,18 @@ static ReturnCode Nbt_ReadTag(uint8_t typeId, bool readTagName, struct Stream* s
 /*########################################################################################################################*
 *--------------------------------------------------ClassicWorld format----------------------------------------------------*
 *#########################################################################################################################*/
+static void* Cw_GetBlocks(struct NbtTag* tag) {
+	void* ptr;
+	if (NbtTag_IsSmall(tag)) {
+		ptr = Mem_Alloc(tag->DataSize, 1, ".cw map blocks");
+		Mem_Copy(ptr, tag->Value.Small, tag->DataSize);
+	} else {
+		ptr = tag->Value.Big;
+		tag->Value.Big = NULL; /* So Nbt_ReadTag doesn't call Mem_Free on World.Blocks */
+	}
+	return ptr;
+}
+
 static void Cw_Callback_1(struct NbtTag* tag) {
 	if (IsTag(tag, "X")) { World.Width  = NbtTag_U16(tag); return; }
 	if (IsTag(tag, "Y")) { World.Height = NbtTag_U16(tag); return; }
@@ -434,17 +446,14 @@ static void Cw_Callback_1(struct NbtTag* tag) {
 
 	if (IsTag(tag, "BlockArray")) {
 		World.Volume = tag->DataSize;
-		if (NbtTag_IsSmall(tag)) {
-			World.Blocks = Mem_Alloc(World.Volume, 1, ".cw map blocks");
-			Mem_Copy(World.Blocks, tag->Value.Small, tag->DataSize);
-		} else {
-			World.Blocks = tag->Value.Big;
-			tag->Value.Big = NULL; /* So Nbt_ReadTag doesn't call Mem_Free on World.Blocks */
-		}
+		World.Blocks = Cw_GetBlocks(tag);
 #ifdef EXTENDED_BLOCKS
 		World.Blocks2 = World.Blocks;
 #endif
 	}
+#ifdef EXTENDED_BLOCKS
+	if (IsTag(tag, "BlockArray2")) World_SetMapUpper(Cw_GetBlocks(tag));
+#endif
 }
 
 static void Cw_Callback_2(struct NbtTag* tag) {
@@ -892,6 +901,9 @@ NBT_DICT, 0,12, 'C','l','a','s','s','i','c','W','o','r','l','d',
 	NBT_END,
 	NBT_I8S,  0,10, 'B','l','o','c','k','A','r','r','a','y', 0,0,0,0,
 };
+static uint8_t cw_map2[18] = {
+	NBT_I8S,  0,11, 'B','l','o','c','k','A','r','r','a','y','2', 0,0,0,0,
+};
 static uint8_t cw_meta_cpe[303] = {
 	NBT_DICT, 0,8,  'M','e','t','a','d','a','t','a',
 		NBT_DICT, 0,3, 'C','P','E',
@@ -1016,9 +1028,17 @@ ReturnCode Cw_Save(struct Stream* stream) {
 		tmp[107] = Math_Deg2Packed(p->SpawnRotY);
 		tmp[112] = Math_Deg2Packed(p->SpawnHeadX);
 	}
-	if ((res = Stream_Write(stream, tmp, sizeof(cw_begin)))) return res;
+	if ((res = Stream_Write(stream, tmp,      sizeof(cw_begin)))) return res;
 	if ((res = Stream_Write(stream, World.Blocks, World.Volume))) return res;
 
+	if (World.Blocks != World.Blocks2) {
+		Mem_Copy(tmp, cw_map2, sizeof(cw_map2));
+		Stream_SetU32_BE(&tmp[14], World.Volume);
+
+		if ((res = Stream_Write(stream, tmp,        sizeof(cw_map2)))) return res;
+		if ((res = Stream_Write(stream, World.Blocks2, World.Volume))) return res;
+	}
+
 	Mem_Copy(tmp, cw_meta_cpe, sizeof(cw_meta_cpe));
 	{
 		Stream_SetU16_BE(&tmp[44], (uint16_t)(LocalPlayer_Instance.ReachDistance * 32));
diff --git a/src/PacketHandlers.c b/src/PacketHandlers.c
index e07332aa7..6bae704b6 100644
--- a/src/PacketHandlers.c
+++ b/src/PacketHandlers.c
@@ -510,10 +510,9 @@ static void Classic_LevelFinalise(uint8_t* data) {
 
 	World_SetNewMap(map_blocks, width, height, length);
 #ifdef EXTENDED_BLOCKS
-	if (cpe_extBlocks) {
-		/* defer allocation of scond map array if possible */
-		World.Blocks2 = map2_blocks ? map2_blocks : map_blocks;
-		Block_SetUsedCount(map2_blocks ? 768 : 256);
+	/* defer allocation of second map array if possible */
+	if (cpe_extBlocks && map2_blocks) {
+		World_SetMapUpper(map2_blocks);
 	}
 #endif
 
diff --git a/src/Program.c b/src/Program.c
index f4e4bc8fb..fe49e758f 100644
--- a/src/Program.c
+++ b/src/Program.c
@@ -105,8 +105,8 @@ int main(int argc, char** argv) {
 	argsCount = Platform_GetCommandLineArgs(argc, argv, args);
 	/* NOTE: Make sure to comment this out before pushing a commit */
 	/* String rawArgs = String_FromConst("UnknownShadow200 fffff 127.0.0.1 25565"); */
-	/* String rawArgs = String_FromConst("UnknownShadow200"); */
-	/* argsCount = String_UNSAFE_Split(&rawArgs, ' ', args, 4); */
+	String rawArgs = String_FromConst("UnknownShadow200"); 
+	argsCount = String_UNSAFE_Split(&rawArgs, ' ', args, 4);
 
 	if (argsCount == 0) {
 		Launcher_Run();
diff --git a/src/World.c b/src/World.c
index 8b8639f19..2e8ee8bb2 100644
--- a/src/World.c
+++ b/src/World.c
@@ -53,7 +53,11 @@ void World_SetNewMap(BlockRaw* blocks, int width, int height, int length) {
 
 	if (!World.Volume) World.Blocks = NULL;
 #ifdef EXTENDED_BLOCKS
-	World.Blocks2 = World.Blocks;
+	/* .cw maps may have set this to a non-NULL when importing */
+	if (!World.Blocks2) {
+		World.Blocks2 = World.Blocks;
+		Block_SetUsedCount(256);
+	}
 #endif
 
 	if (Env_EdgeHeight == -1) {
@@ -74,6 +78,13 @@ CC_NOINLINE void World_SetDimensions(int width, int height, int length) {
 	World.MaxZ = length - 1;
 }
 
+#ifdef EXTENDED_BLOCKS
+void World_SetMapUpper(BlockRaw* blocks) {
+	World.Blocks2 = blocks;
+	Block_SetUsedCount(768);
+}
+#endif
+
 
 #ifdef EXTENDED_BLOCKS
 void World_SetBlock(int x, int y, int z, BlockID block) {
diff --git a/src/World.h b/src/World.h
index 0d0fb8c53..8777f71f2 100644
--- a/src/World.h
+++ b/src/World.h
@@ -47,6 +47,8 @@ CC_NOINLINE void World_SetDimensions(int width, int height, int length);
 
 #ifdef EXTENDED_BLOCKS
 extern int Block_IDMask;
+/* Sets World.Blocks2 and updates internal state for more than 256 blocks. */
+void World_SetMapUpper(BlockRaw* blocks);
 
 /* Gets the block at the given coordinates. */
 /* NOTE: Does NOT check that the coordinates are inside the map. */