diff --git a/src/app/rom.cc b/src/app/rom.cc
index 0013855e..17b06f5a 100644
--- a/src/app/rom.cc
+++ b/src/app/rom.cc
@@ -89,6 +89,8 @@ void ROM::LoadAllGraphicsData() {
 
     buffer_pos += sizeof(data);
   }
+
+  master_gfx_bin_ = buffer;
 }
 
 uchar *ROM::DecompressGraphics(int pos, int size) {
@@ -123,46 +125,57 @@ uchar *ROM::Decompress(int pos, int size, bool reversed) {
     length += 1;  // each commands is at least of size 1 even if index 00
 
     switch (cmd) {
-      case 00:  // Direct Copy (Could be replaced with a MEMCPY)
+      case kCommandDirectCopy:
         for (int i = 0; i < length; i++) {
           buffer[buffer_pos++] = current_rom_[pos++];
         }
         // Do not advance in the ROM
         break;
-      case 01:  // Byte Fill
+      case kCommandByteFill:
         for (int i = 0; i < length; i++) {
           buffer[buffer_pos++] = current_rom_[pos];
         }
         pos += 1;  // Advance 1 byte in the ROM
         break;
-      case 02:  // Word Fill
+      case kCommandWordFill:
         for (int i = 0; i < length; i += 2) {
           buffer[buffer_pos++] = current_rom_[pos];
           buffer[buffer_pos++] = current_rom_[pos + 1];
         }
         pos += 2;  // Advance 2 byte in the ROM
         break;
-      case 03:  // Increasing Fill
-      {
+      case kCommandIncreasingFill: {
         uchar inc_byte = current_rom_[pos];
         for (int i = 0; i < length; i++) {
           buffer[buffer_pos++] = inc_byte++;
         }
         pos += 1;  // Advance 1 byte in the ROM
       } break;
-      case 04:  // Repeat (Reversed byte order for maps)
-      {
+      case kCommandRepeatingBytes: {
         ushort s1 = ((current_rom_[pos + 1] & 0xFF) << 8);
         ushort s2 = ((current_rom_[pos] & 0xFF));
-        auto addr = (ushort)(s1 | s2);
+        // Reversed byte order for overworld maps
         if (reversed) {
-          addr = (ushort)(s2 | s1);
+          auto addr = (current_rom_[pos + 2]) | ((current_rom_[pos + 1]) << 8);
+          if (addr > buffer_pos) {
+            std::cout << "size error" << std::endl;
+          }
+
+          if (buffer_pos + length >= size) {
+            size *= 2;
+            buffer = new uchar[size];
+            std::cout << "Reallocate buffer" << std::endl;
+          }
+          memcpy(buffer + buffer_pos, current_rom_ + pos, length);
+          pos += 2;
+        } else {
+          auto addr = (ushort)(s1 | s2);
+          for (int i = 0; i < length; i++) {
+            buffer[buffer_pos] = buffer[addr + i];
+            buffer_pos++;
+          }
+          pos += 2;  // Advance 2 bytes in the ROM
         }
-        for (int i = 0; i < length; i++) {
-          buffer[buffer_pos] = buffer[addr + i];
-          buffer_pos++;
-        }
-        pos += 2;  // Advance 2 bytes in the ROM
       } break;
     }
   }
diff --git a/src/app/rom.h b/src/app/rom.h
index d4de4f12..37dc8e0a 100644
--- a/src/app/rom.h
+++ b/src/app/rom.h
@@ -21,9 +21,19 @@
 namespace yaze {
 namespace app {
 
+struct OWMapTiles {
+  std::vector<std::vector<ushort>> light_world;    // 64 maps * (32*32 tiles)
+  std::vector<std::vector<ushort>> dark_world;     // 64 maps * (32*32 tiles)
+  std::vector<std::vector<ushort>> special_world;  // 32 maps * (32*32 tiles)
+} typedef OWMapTiles;
+
+constexpr int kCommandDirectCopy = 0;
+constexpr int kCommandByteFill = 1;
+constexpr int kCommandWordFill = 2;
+constexpr int kCommandIncreasingFill = 3;
+constexpr int kCommandRepeatingBytes = 4;
 constexpr uchar kGraphicsBitmap[8] = {0x80, 0x40, 0x20, 0x10,
                                       0x08, 0x04, 0x02, 0x01};
-
 class ROM {
  public:
   void Close();
@@ -49,12 +59,14 @@ class ROM {
   bool isLoaded() const { return is_loaded_; }
   auto Renderer() { return sdl_renderer_; }
   auto GetGraphicsBin() const { return graphics_bin_; }
+  auto GetMasterGraphicsBin() const { return master_gfx_bin_; }
   auto GetVRAM() const { return pseudo_vram_; }
 
  private:
   int num_sheets_ = 0;
   long size_ = 0;
   uchar* current_rom_;
+  uchar* master_gfx_bin_;
   uchar title[21] = "ROM Not Loaded";
   bool is_loaded_ = false;
   bool isbpp3[core::constants::NumberOfSheets];