diff --git a/SecurityPkg/Tcg/Opal/OpalPassword/OpalPasswordPei.c b/SecurityPkg/Tcg/Opal/OpalPassword/OpalPasswordPei.c
index 0fb6b1bf41..1ee55105e4 100644
--- a/SecurityPkg/Tcg/Opal/OpalPassword/OpalPasswordPei.c
+++ b/SecurityPkg/Tcg/Opal/OpalPassword/OpalPasswordPei.c
@@ -49,7 +49,9 @@ EFI_GUID  mOpalDeviceLockBoxGuid = OPAL_DEVICE_LOCKBOX_GUID;
   function shall return EFI_DEVICE_ERROR.
 
   @param  This                         Indicates a pointer to the calling context.
-  @param  MediaId                      ID of the medium to receive data from.
+  @param  MediaId                      ID of the medium to receive data from. If there is no
+                                       block IO protocol supported by the physical device, the
+                                       value of MediaId is undefined.
   @param  Timeout                      The timeout, in 100ns units, to use for the execution
                                        of the security protocol command. A Timeout value of 0
                                        means that this function will wait indefinitely for the
@@ -148,7 +150,9 @@ SecurityReceiveData (
   shall return EFI_DEVICE_ERROR.
 
   @param  This                         Indicates a pointer to the calling context.
-  @param  MediaId                      ID of the medium to receive data from.
+  @param  MediaId                      ID of the medium to receive data from. If there is no
+                                       block IO protocol supported by the physical device, the
+                                       value of MediaId is undefined.
   @param  Timeout                      The timeout, in 100ns units, to use for the execution
                                        of the security protocol command. A Timeout value of 0
                                        means that this function will wait indefinitely for the