--- ../src-base/minecraft/net/minecraft/network/play/server/S21PacketChunkData.java
+++ ../src-work/minecraft/net/minecraft/network/play/server/S21PacketChunkData.java
@@ -45,7 +45,7 @@
 
     private void deflate()
     {
-        Deflater deflater = new Deflater(-1);
+        Deflater deflater = new Deflater(4); // Spigot -1 -> 4
         try
         {
             deflater.setInput(this.field_149278_f, 0, this.field_149278_f.length);
@@ -198,8 +198,10 @@
             if (aextendedblockstorage[l] != null && (!p_149269_1_ || !aextendedblockstorage[l].isEmpty()) && (p_149269_2_ & 1 << l) != 0)
             {
                 nibblearray = aextendedblockstorage[l].getMetadataArray();
-                System.arraycopy(nibblearray.data, 0, abyte, j, nibblearray.data.length);
-                j += nibblearray.data.length;
+                // Spigot start
+                nibblearray.copyToByteArray(abyte, j);
+                j += nibblearray.getByteLength();
+                // Spigot end
             }
         }
 
@@ -208,8 +210,10 @@
             if (aextendedblockstorage[l] != null && (!p_149269_1_ || !aextendedblockstorage[l].isEmpty()) && (p_149269_2_ & 1 << l) != 0)
             {
                 nibblearray = aextendedblockstorage[l].getBlocklightArray();
-                System.arraycopy(nibblearray.data, 0, abyte, j, nibblearray.data.length);
-                j += nibblearray.data.length;
+                // Spigot start
+                nibblearray.copyToByteArray(abyte, j);
+                j += nibblearray.getByteLength();
+                // Spigot end
             }
         }
 
@@ -220,8 +224,10 @@
                 if (aextendedblockstorage[l] != null && (!p_149269_1_ || !aextendedblockstorage[l].isEmpty()) && (p_149269_2_ & 1 << l) != 0)
                 {
                     nibblearray = aextendedblockstorage[l].getSkylightArray();
-                    System.arraycopy(nibblearray.data, 0, abyte, j, nibblearray.data.length);
-                    j += nibblearray.data.length;
+                    // Spigot start
+                    nibblearray.copyToByteArray(abyte, j);
+                    j += nibblearray.getByteLength();
+                    // Spigot end
                 }
             }
         }
@@ -233,8 +239,10 @@
                 if (aextendedblockstorage[l] != null && (!p_149269_1_ || !aextendedblockstorage[l].isEmpty()) && aextendedblockstorage[l].getBlockMSBArray() != null && (p_149269_2_ & 1 << l) != 0)
                 {
                     nibblearray = aextendedblockstorage[l].getBlockMSBArray();
-                    System.arraycopy(nibblearray.data, 0, abyte, j, nibblearray.data.length);
-                    j += nibblearray.data.length;
+                    // Spigot start
+                    nibblearray.copyToByteArray(abyte, j);
+                    j += nibblearray.getByteLength();
+                    // Spigot end
                 }
             }
         }
@@ -293,4 +301,4 @@
             public int field_150281_c;
             private static final String __OBFID = "CL_00001305";
         }
-}
+}