diff --git a/DS_Map/DSUtils/ARM9.cs b/DS_Map/DSUtils/ARM9.cs
index 8c57c25..639c7fa 100644
--- a/DS_Map/DSUtils/ARM9.cs
+++ b/DS_Map/DSUtils/ARM9.cs
@@ -23,6 +23,7 @@ namespace DSPRE {
             }
         }
         public static bool Decompress(string path) {
+
             Process decompress = DSUtils.CreateDecompressProcess(path);
             decompress.Start();
             decompress.WaitForExit();
diff --git a/DS_Map/Main Window.cs b/DS_Map/Main Window.cs
index fe6a1c6..0d262bd 100644
--- a/DS_Map/Main Window.cs	
+++ b/DS_Map/Main Window.cs	
@@ -103,7 +103,7 @@ namespace DSPRE
 
         /* ROM Information */
         public static string gameCode;
-        public static byte europeByte;
+        public static byte revisionByte;
         public RomInfo romInfo;
         public Dictionary<ushort /*evFile*/, ushort /*header*/> eventToHeader = new Dictionary<ushort, ushort>();
 
@@ -666,8 +666,6 @@ namespace DSPRE
             string workDir = DSUtils.WorkDirPathFromFile(openRom.FileName);
             AppLogger.Info(workDir + " will be used as the working directory for the ROM.");
 
-
-
             int userchoice = UnpackRomCheckUserChoice(workDir);
             switch (userchoice)
             {
@@ -825,7 +823,7 @@ namespace DSPRE
 
             if (RomInfo.gameLanguage == GameLanguages.English)
             {
-                if (europeByte == 0x0A)
+                if (revisionByte == 0x0A)
                 {
                     languageLabel.Text += " [Europe]";
                 }
@@ -893,6 +891,12 @@ namespace DSPRE
             gameIcon.Refresh();  // Paint game icon
             AppLogger.Debug("Game icon refreshed.");
 
+            if (!CheckAndDecompressARM9())
+            {
+                AppLogger.Error("ARM9 decompression failed. Aborting.");
+                return;
+            }
+
             ReadROMInitData();
             AppLogger.Info("ROM initialization data loaded.");
         }
@@ -904,26 +908,39 @@ namespace DSPRE
             {
                 gameCode = Encoding.UTF8.GetString(br.ReadBytes(4));
                 br.BaseStream.Position = 0x1E;
-                europeByte = br.ReadByte();
+                revisionByte = br.ReadByte();
             }
         }
 
+        private bool CheckAndDecompressARM9()
+        {
+            if (!ARM9.CheckCompressionMark())
+            {
+                return true; // ARM9 is not compressed, proceed normally
+            }
+
+            if (!RomInfo.gameFamily.Equals(GameFamilies.HGSS))
+            {
+                MessageBox.Show("Unexpected compressed ARM9. It is advised that you double check the ARM9.");
+                return false;
+            }
+
+            ARM9.EditSize(-12); // Fix ARM9 size before decompression
+
+            if (!ARM9.Decompress(RomInfo.arm9Path))
+            {
+                MessageBox.Show("ARM9 decompression failed. The program can't proceed.\nAborting.",
+                            "Error with ARM9 decompression", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                return false;
+            }
+
+            AppLogger.Info("ARM9 decompressed and size fixed.");
+
+            return true;
+        }
+
         private void ReadROMInitData()
         {
-            if (ARM9.CheckCompressionMark())
-            {
-                if (!RomInfo.gameFamily.Equals(GameFamilies.HGSS))
-                {
-                    MessageBox.Show("Unexpected compressed ARM9. It is advised that you double check the ARM9.");
-                }
-                if (!ARM9.Decompress(RomInfo.arm9Path))
-                {
-                    MessageBox.Show("ARM9 decompression failed. The program can't proceed.\nAborting.",
-                                "Error with ARM9 decompression", MessageBoxButtons.OK, MessageBoxIcon.Error);
-                    return;
-                }
-            }
-
             /* Setup essential editors */
             EditorPanels.headerEditor.SetupHeaderEditor(this);