diff --git a/Ryujinx.HLE/HOS/Services/FspSrv/IFileSystemProxy.cs b/Ryujinx.HLE/HOS/Services/FspSrv/IFileSystemProxy.cs
index 8764792c33..57932f053c 100644
--- a/Ryujinx.HLE/HOS/Services/FspSrv/IFileSystemProxy.cs
+++ b/Ryujinx.HLE/HOS/Services/FspSrv/IFileSystemProxy.cs
@@ -28,6 +28,7 @@ namespace Ryujinx.HLE.HOS.Services.FspSrv
                 { 18,   OpenSdCardFileSystem                     },
                 { 51,   OpenSaveDataFileSystem                   },
                 { 52,   OpenSaveDataFileSystemBySystemSaveDataId },
+                { 53,   OpenReadOnlySaveDataFileSystem           },
                 { 200,  OpenDataStorageByCurrentProcess          },
                 { 202,  OpenDataStorageByDataId                  },
                 { 203,  OpenPatchDataStorageByCurrentProcess     },
@@ -135,6 +136,14 @@ namespace Ryujinx.HLE.HOS.Services.FspSrv
             return 0;
         }
 
+        // OpenReadOnlySaveDataFileSystem(u8 save_data_space_id, ...) -> object<> ...
+        public long OpenReadOnlySaveDataFileSystem(ServiceCtx context)
+        {
+            LoadSaveDataFileSystem(context);
+
+            return 0;
+        }
+
         // OpenDataStorageByCurrentProcess() -> object<nn::fssrv::sf::IStorage> dataStorage
         public long OpenDataStorageByCurrentProcess(ServiceCtx context)
         {