diff --git a/ArcFormats/AudioOGG.cs b/ArcFormats/AudioOGG.cs
index 63bbe1db..a332ff3a 100644
--- a/ArcFormats/AudioOGG.cs
+++ b/ArcFormats/AudioOGG.cs
@@ -138,6 +138,6 @@ namespace GameRes.Formats
 
         public static AudioFormat Instance { get { return s_OggFormat.Value; } }
 
-        static readonly Lazy<AudioFormat> s_OggFormat = new Lazy<AudioFormat> (() => FormatCatalog.Instance.AudioFormats.FirstOrDefault (x => x.Tag == "OGG"));
+        static readonly ResourceInstance<AudioFormat> s_OggFormat = new ResourceInstance<AudioFormat> ("OGG");
     }
 }
diff --git a/ArcFormats/MAI/ArcMAI.cs b/ArcFormats/MAI/ArcMAI.cs
index 68e6056e..ea0c1701 100644
--- a/ArcFormats/MAI/ArcMAI.cs
+++ b/ArcFormats/MAI/ArcMAI.cs
@@ -100,19 +100,16 @@ namespace GameRes.Formats.MAI
                     return null;
                 var offset = file.View.ReadUInt32 (index_offset+0x10);
                 var entry = new AutoEntry (Path.Combine (current_folder, name), () => {
-                    uint signature = file.View.ReadUInt32 (offset);
                     if (is_mask_arc)
-                        return ImageFormat.FindByTag ("MSK/MAI");
-                    else if (0x4d43 == (signature & 0xffff)) // 'CM'
-                        return ImageFormat.FindByTag ("CM/MAI");
-                    else if (0x4d41 == (signature & 0xffff)) // 'AM'
-                        return ImageFormat.FindByTag ("AM/MAI");
-                    else if (0x4d42 == (signature & 0xffff)) // 'BM'
-                        return ImageFormat.Bmp;
-                    else if (signature != 0)
-                        return FormatCatalog.Instance.LookupSignature (signature).FirstOrDefault();
-                    else
-                        return null;
+                        return s_MskFormat.Value;
+                    uint signature = file.View.ReadUInt32 (offset);
+                    switch (signature & 0xFFFF)
+                    {
+                    case 0x4D43: return s_CmFormat.Value;
+                    case 0x4D41: return s_AmFormat.Value;
+                    case 0x4D42: return ImageFormat.Bmp;
+                    default: return AutoEntry.DetectFileType (signature);
+                    }
                 });
                 entry.Offset = offset;
                 entry.Size = file.View.ReadUInt32 (index_offset+0x14);
@@ -123,5 +120,9 @@ namespace GameRes.Formats.MAI
             }
             return new ArcFile (file, this, dir);
         }
+
+        static readonly ResourceInstance<ImageFormat> s_AmFormat  = new ResourceInstance<ImageFormat> ("AM/MAI");
+        static readonly ResourceInstance<ImageFormat> s_CmFormat  = new ResourceInstance<ImageFormat> ("CM/MAI");
+        static readonly ResourceInstance<ImageFormat> s_MskFormat = new ResourceInstance<ImageFormat> ("MSK/MAI");
     }
 }
diff --git a/ArcFormats/Majiro/ImageRCT.cs b/ArcFormats/Majiro/ImageRCT.cs
index 45a92190..79d1454b 100644
--- a/ArcFormats/Majiro/ImageRCT.cs
+++ b/ArcFormats/Majiro/ImageRCT.cs
@@ -152,7 +152,7 @@ namespace GameRes.Formats.Majiro
             return ImageData.Create (meta, PixelFormats.Bgr24, null, pixels, (int)meta.Width*3);
         }
 
-        static readonly Lazy<ImageFormat> s_rc8_format = new Lazy<ImageFormat> (() => FindByTag ("RC8"));
+        static readonly ResourceInstance<ImageFormat> s_rc8_format = new ResourceInstance<ImageFormat> ("RC8");
 
         ImageData ApplyMaskToImage (RctMetaData info, byte[] image, string mask_name)
         {
@@ -298,7 +298,7 @@ namespace GameRes.Formats.Majiro
             return options.Password;
         }
 
-        static readonly Lazy<ArchiveFormat> s_Majiro = new Lazy<ArchiveFormat> (() => FormatCatalog.Instance.ArcFormats.FirstOrDefault (x => x.Tag == "MAJIRO"));
+        static readonly ResourceInstance<ArchiveFormat> s_Majiro = new ResourceInstance<ArchiveFormat> ("MAJIRO");
 
         private string FindImageKey ()
         {