diff --git a/arch/arm/src/nrf52/sdc/core_cm4.h b/arch/arm/src/nrf52/sdc/core_cm4.h
deleted file mode 100644
index ec453d5dba..0000000000
--- a/arch/arm/src/nrf52/sdc/core_cm4.h
+++ /dev/null
@@ -1,41 +0,0 @@
-/****************************************************************************
- * arch/arm/src/nrf52/sdc/core_cm4.h
- *
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.  The
- * ASF licenses this file to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance with the
- * License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
- * License for the specific language governing permissions and limitations
- * under the License.
- *
- ****************************************************************************/
-
-#ifndef __ARCH_ARM_SRC_NRF52_SDC_CORE_CM4_H
-#define __ARCH_ARM_SRC_NRF52_SDC_CORE_CM4_H
-
-/****************************************************************************
- * Preprocessor Definitions
- ****************************************************************************/
-
-/* These are the definitions needed from CMSIS */
-
-#ifdef __cplusplus
-#  define   __I     volatile
-#else
-#  define   __I     volatile const
-#endif
-#define     __O     volatile
-#define     __IO    volatile
-#define     __IM    volatile const
-#define     __OM    volatile
-#define     __IOM   volatile
-
-#endif /* __ARCH_ARM_SRC_NRF52_SDC_CORE_CM4_H */