diff --git a/nms-patches/ChunkRegionLoader.patch b/nms-patches/ChunkRegionLoader.patch
index d657e19aee..22b188362e 100644
--- a/nms-patches/ChunkRegionLoader.patch
+++ b/nms-patches/ChunkRegionLoader.patch
@@ -9,8 +9,37 @@
  
      public ChunkRegionLoader(File file, DataFixer datafixer) {
          this.c = file;
-@@ -50,12 +50,13 @@
+@@ -48,15 +48,54 @@
+         return nbttagcompound != null ? nbttagcompound : this.b(generatoraccess, i, j);
+     }
  
++    // CraftBukkit start
++    private boolean check(ChunkProviderServer cps, int x, int z) throws IOException {
++        com.google.common.base.Preconditions.checkState(org.bukkit.Bukkit.isPrimaryThread(), "primary thread");
++
++        if (cps.isLoaded(x, z)) {
++            return true;
++        }
++
++        if (RegionFileCache.chunkExists(this.c, x, z)) {
++            NBTTagCompound nbt = RegionFileCache.d(this.c, x, z);
++            if (nbt != null) {
++                NBTTagCompound level = nbt.getCompound("Level");
++                if (level.getBoolean("TerrainPopulated")) {
++                    return true;
++                }
++
++                ChunkStatus status = ChunkStatus.a(level.getString("Status"));
++                if (status != null && status.a(ChunkStatus.DECORATED)) {
++                    return true;
++                }
++            }
++        }
++
++        return false;
++    }
++    // CraftBukkit end
++
      @Nullable
      private NBTTagCompound b(GeneratorAccess generatoraccess, int i, int j) throws IOException {
 -        DataInputStream datainputstream = RegionFileCache.d(this.c, i, j);
@@ -24,9 +53,21 @@
 -            NBTTagCompound nbttagcompound = NBTCompressedStreamTools.a(datainputstream);
 +            // CraftBukkit end
              int k = nbttagcompound.hasKeyOfType("DataVersion", 99) ? nbttagcompound.getInt("DataVersion") : -1;
++            // CraftBukkit start
++            if (k < 1466) {
++                NBTTagCompound level = nbttagcompound.getCompound("Level");
++                if (level.getBoolean("TerrainPopulated") && !level.getBoolean("LightPopulated")) {
++                    ChunkProviderServer cps = ((WorldServer) generatoraccess).getChunkProviderServer();
++                    if (check(cps, i - 1, j) && check(cps, i - 1, j - 1) && check(cps, i, j - 1)) {
++                        level.setBoolean("LightPopulated", true);
++                    }
++                }
++            }
++            // CraftBukkit end
  
              if (k < 1493) {
-@@ -78,13 +79,29 @@
+                 nbttagcompound = GameProfileSerializer.a(this.d, DataFixTypes.CHUNK, nbttagcompound, k, 1493);
+@@ -78,13 +117,29 @@
          }
      }
  
@@ -56,7 +97,7 @@
              Chunk chunk = this.a(generatoraccess, i, j, nbttagcompound);
  
              if (chunk != null) {
-@@ -93,6 +110,9 @@
+@@ -93,6 +148,9 @@
              }
  
              return chunk;
@@ -66,7 +107,7 @@
          }
      }
  
-@@ -121,7 +141,7 @@
+@@ -121,7 +179,7 @@
      }
  
      @Nullable
@@ -75,7 +116,7 @@
          if (nbttagcompound.hasKeyOfType("Level", 10) && nbttagcompound.getCompound("Level").hasKeyOfType("Status", 8)) {
              ChunkStatus.Type chunkstatus_type = this.a(nbttagcompound);
  
-@@ -140,10 +160,28 @@
+@@ -140,10 +198,28 @@
                          ChunkRegionLoader.a.error("Chunk file at {},{} is in the wrong location; relocating. (Expected {}, {}, got {}, {})", Integer.valueOf(i), Integer.valueOf(j), Integer.valueOf(i), Integer.valueOf(j), Integer.valueOf(chunk.locX), Integer.valueOf(chunk.locZ));
                          nbttagcompound1.setInt("xPos", i);
                          nbttagcompound1.setInt("zPos", j);
@@ -105,7 +146,7 @@
                  }
              }
          } else {
-@@ -158,7 +196,7 @@
+@@ -158,7 +234,7 @@
              ChunkStatus.Type chunkstatus_type = this.a(nbttagcompound);
  
              if (chunkstatus_type == ChunkStatus.Type.LEVELCHUNK) {
@@ -114,7 +155,7 @@
              } else {
                  NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("Level");
  
-@@ -204,19 +242,30 @@
+@@ -204,19 +280,30 @@
      }
  
      public synchronized boolean a() {
@@ -149,7 +190,7 @@
  
                  if (nbttagcompound != null) {
                      try {
-@@ -228,7 +277,7 @@
+@@ -228,7 +315,7 @@
  
                  flag = true;
              } finally {
@@ -158,7 +199,7 @@
              }
  
              return flag;
-@@ -248,10 +297,14 @@
+@@ -248,10 +335,14 @@
      }
  
      private void b(ChunkCoordIntPair chunkcoordintpair, NBTTagCompound nbttagcompound) throws IOException {
@@ -174,7 +215,7 @@
          if (this.e != null) {
              this.e.a(chunkcoordintpair.a());
          }
-@@ -264,15 +317,16 @@
+@@ -264,15 +355,16 @@
  
      public void c() {
          try {
@@ -194,7 +235,7 @@
          }
  
      }
-@@ -301,7 +355,7 @@
+@@ -301,7 +393,7 @@
  
          if (abiomebase != null) {
              for (int k = 0; k < abiomebase.length; ++k) {
@@ -203,7 +244,7 @@
              }
          }
  
-@@ -383,7 +437,7 @@
+@@ -383,7 +475,7 @@
          int[] aint = new int[abiomebase.length];
  
          for (int i = 0; i < abiomebase.length; ++i) {
@@ -212,7 +253,7 @@
          }
  
          nbttagcompound.setIntArray("Biomes", aint);
-@@ -485,7 +539,7 @@
+@@ -485,7 +577,7 @@
          }
  
          ChunkConverter chunkconverter = nbttagcompound.hasKeyOfType("UpgradeData", 10) ? new ChunkConverter(nbttagcompound.getCompound("UpgradeData")) : ChunkConverter.a;
@@ -221,7 +262,7 @@
              return block.getBlockData().isAir();
          };
          RegistryBlocks registryblocks = Block.REGISTRY;
-@@ -497,7 +551,7 @@
+@@ -497,7 +589,7 @@
          Block.REGISTRY.getClass();
          ProtoChunkTickList protochunkticklist = new ProtoChunkTickList(predicate, function, registryblocks1::get, new ChunkCoordIntPair(i, j));
  
@@ -230,7 +271,7 @@
              return fluidtype == FluidTypes.a;
          };
          registryblocks = FluidType.c;
-@@ -505,7 +559,7 @@
+@@ -505,7 +597,7 @@
          function = registryblocks::b;
          registryblocks1 = FluidType.c;
          FluidType.c.getClass();
@@ -239,7 +280,7 @@
          long i1 = nbttagcompound.getLong("InhabitedTime");
          Chunk chunk = new Chunk(generatoraccess.getMinecraftWorld(), i, j, abiomebase, chunkconverter, protochunkticklist, protochunkticklist1, i1);
  
-@@ -852,17 +906,29 @@
+@@ -852,17 +944,29 @@
      }
  
      @Nullable
@@ -271,7 +312,7 @@
          });
      }
  
-@@ -876,8 +942,14 @@
+@@ -876,8 +980,14 @@
          }
      }