diff --git a/csst_common/data_manager.py b/csst_common/data_manager.py
index e54da2d8b43d9999b4a8f94467d1a2af034cc85b..aa6af1a7d9cb5037db881d93448a059f7fa600b6 100644
--- a/csst_common/data_manager.py
+++ b/csst_common/data_manager.py
@@ -541,51 +541,46 @@ class CsstMsDataManager:
 
     def get_bias(self, detector=6):
         """ get bias data """
-        if self.custom_bias is None:
-            return os.path.join(
-                self.path_aux,
-                "C6.2_ref_crds",
-                "csst_msc_{}_{:02d}_{:04d}.fits".format(
-                    "bias", detector, 1 if self.ref_version is None else self.ref_version
-                )
-            )
+        fp = os.path.join(
+            self.path_aux,
+            "C6.2_ref_crds",
+            "csst_msc_ms_{}_{:02d}_{:04d}.fits".format("bias", detector, 1)
+        )
+        if not os.path.exists(fp):
+            raise FileNotFoundError(fp)
         else:
-            return self.custom_bias.format("bias", detector)
+            return fp
 
     def get_dark(self, detector=6):
         """ get dark data """
-        if self.custom_dark is None:
-            return os.path.join(
-                self.path_aux,
-                "C6.2_ref_crds",
-                "csst_msc_{}_{:02d}_{:04d}.fits".format(
-                    "dark", detector, 1 if self.ref_version is None else self.ref_version
-                )
-            )
+        fp = os.path.join(
+            self.path_aux,
+            "C6.2_ref_crds",
+            "csst_msc_ms_{}_{:02d}_{:04d}.fits".format("dark", detector, 1)
+        )
+        if not os.path.exists(fp):
+            raise FileNotFoundError(fp)
         else:
-            return self.custom_dark.format("dark", detector)
+            return fp
 
     def get_flat(self, detector=6):
         """ get flat data """
-        if self.custom_flat is None:
-            return os.path.join(
-                self.path_aux,
-                "C6.2_ref_crds",
-                "csst_msc_{}_{:02d}_{:04d}.fits".format(
-                    "flat", detector, 1 if self.ref_version is None else self.ref_version
-                )
-            )
+        fp = os.path.join(
+            self.path_aux,
+            "C6.2_ref_crds",
+            "csst_msc_ms_{}_{:02d}_{:04d}.fits".format("ledflat", detector, 1)
+        )
+        if not os.path.exists(fp):
+            raise FileNotFoundError(fp)
         else:
-            return self.custom_flat.format("flat", detector)
+            return fp
 
     def get_shutter(self, detector=6):
         """ get flat data """
         fp = os.path.join(
             self.path_aux,
-            "C6.2_ref_mbi",
-            "CSST_MSC_MS_SHUTTER_{:02d}_{:04d}.fits".format(
-                detector, 1 if self.ref_version is None else self.ref_version
-            )
+            "C6.2_ref_crds",
+            "csst_msc_ms_{}_{:02d}_{:04d}.fits".format("shutter", detector, 1)
         )
         if not os.path.exists(fp):
             raise FileNotFoundError(fp)