This works but lags, only for 1.8 server.

src/main/java/us/myles/ViaVersion/protocols/protocol1_9_3to1_9_1_2/Chunk1_9_1_2.java

@@ -14,7 +14,8 @@ public class Chunk1_9_1_2 implements Chunk {
     private int z;
     private boolean groundUp;
     private int bitmask;
-    private byte[] sections;
+    private final ChunkSection1_9_1_2[] sections;
+    private final byte[] biomeData;
     List<CompoundTag> blockEntities;
 
 }

src/main/java/us/myles/ViaVersion/protocols/protocol1_9_3to1_9_1_2/Chunk1_9_1_2Type.java

@@ -7,6 +7,7 @@ import us.myles.ViaVersion.api.type.Type;
 import us.myles.ViaVersion.api.type.types.minecraft.BaseChunkType;
 
 import java.util.ArrayList;
+import java.util.BitSet;
 import java.util.List;
 
 public class Chunk1_9_1_2Type extends BaseChunkType {
@@ -23,15 +24,39 @@ public class Chunk1_9_1_2Type extends BaseChunkType {
         int primaryBitmask = Type.VAR_INT.read(input);
         int size = Type.VAR_INT.read(input);
 
-        byte[] sections = new byte[size];
-        input.readBytes(sections);
+//        byte[] sections = new byte[size];
+//        input.readBytes(sections);
+
+        BitSet usedSections = new BitSet(16);
+        ChunkSection1_9_1_2[] sections = new ChunkSection1_9_1_2[16];
+        byte[] biomeData = null;
+
+        // Calculate section count from bitmask
+        for (int i = 0; i < 16; i++) {
+            if ((primaryBitmask & (1 << i)) != 0) {
+                usedSections.set(i);
+            }
+        }
+        int sectionCount = usedSections.cardinality(); // the amount of sections set
+        // Read sections
+        for (int i = 0; i < 16; i++) {
+            if (!usedSections.get(i)) continue; // Section not set
+            ChunkSection1_9_1_2 section = new ChunkSection1_9_1_2();
+            sections[i] = section;
+
+            short bitsPerBlock = input.readUnsignedByte();
+            Integer[] palette = Type.VAR_INT_ARRAY.read(input); // 0 if none
+            // Read blocks
+            Long[] data = Type.LONG_ARRAY.read(input);
+
+        }
 
         int blockEntities = Type.VAR_INT.read(input);
         List<CompoundTag> nbtData = new ArrayList<>();
         for (int i = 0; i < blockEntities; i++) {
             nbtData.add(Type.NBT.read(input));
         }
-        return new Chunk1_9_1_2(chunkX, chunkZ, groundUp, primaryBitmask, sections, nbtData);
+        return new Chunk1_9_1_2(chunkX, chunkZ, groundUp, primaryBitmask, sections, new byte[0], nbtData);
     }
 
     @Override
@@ -47,7 +72,7 @@ public class Chunk1_9_1_2Type extends BaseChunkType {
         Type.VAR_INT.write(buffer, chunk.getBitmask());
 
         Type.VAR_INT.write(buffer, chunk.getSections().length);
-        buffer.writeBytes(chunk.getSections());
+//        buffer.writeBytes(chunk.getSections());
 
         // no block entities as it's earlier
     }

src/main/java/us/myles/ViaVersion/protocols/protocol1_9_3to1_9_1_2/FakeTileEntity.java

@@ -104,7 +104,7 @@ public class FakeTileEntity {
             tag.put(new IntTag("x", x));
             tag.put(new IntTag("y", y));
             tag.put(new IntTag("z", z));
-            System.out.println("Found tile entity " + block + " at position " + x + " " + y + " " + z);
+//            System.out.println("Found tile entity " + block + " at position " + x + " " + y + " " + z);
             return tag;
         }
         return null;

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/chunks/ChunkSection1_9to1_8.java

@@ -47,7 +47,7 @@ public class ChunkSection1_9to1_8 {
 
     public int getBlockId(int x, int y, int z){
         int index = blocks[index(x, y, z)];
-        return palette.indexOf(index) >> 4;
+        return palette.get(index) >> 4;
     }
 
     /**

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/types/ChunkType.java

@@ -97,6 +97,7 @@ public class ChunkType extends PartialType<Chunk, ClientChunks> {
                 int mask = blockBuf.get();
                 int type = mask >> 4;
                 int data = mask & 0xF;
+
                 section.setBlock(j, type, data);
             }
         }
@@ -161,8 +162,10 @@ public class ChunkType extends PartialType<Chunk, ClientChunks> {
                 for (int y = 0; y < 16; y++)
                     for (int z = 0; z < 16; z++) {
                         int block = section.getBlockId(x, y, z);
-                        if (FakeTileEntity.hasBlock(block))
-                            tags.add(FakeTileEntity.getFromBlock(x * chunk.getX(), y, z * chunk.getZ(), block));
+                        if (FakeTileEntity.hasBlock(block)) {
+                            // NOT SURE WHY Y AND Z WORK THIS WAY, TODO: WORK OUT WHY THIS IS OR FIX W/E BROKE IT
+                            tags.add(FakeTileEntity.getFromBlock(x + (chunk.getX() << 4), z + (i << 4), y + (chunk.getZ() << 4), block));
+                        }
                     }
 
             if (!section.hasSkyLight()) continue; // No sky light, we're done here.