diff --git a/examples/make.mk b/examples/make.mk
index 26065c02..fa909ddc 100644
--- a/examples/make.mk
+++ b/examples/make.mk
@@ -90,13 +90,13 @@ CFLAGS += \
   -ffunction-sections \
   -fsingle-precision-constant \
   -fno-strict-aliasing \
-  -Wdouble-promotion \
-  -Wstrict-prototypes \
-  -Wstrict-overflow \
   -Wall \
   -Wextra \
   -Werror \
   -Wfatal-errors \
+  -Wdouble-promotion \
+  -Wstrict-prototypes \
+  -Wstrict-overflow \
   -Werror-implicit-function-declaration \
   -Wfloat-equal \
   -Wundef \
diff --git a/hw/bsp/nrf/family.mk b/hw/bsp/nrf/family.mk
index 609e2da0..d8283a9e 100644
--- a/hw/bsp/nrf/family.mk
+++ b/hw/bsp/nrf/family.mk
@@ -16,9 +16,6 @@ CFLAGS += \
 # suppress warning caused by vendor mcu driver
 CFLAGS += -Wno-error=undef -Wno-error=unused-parameter -Wno-error=cast-align -Wno-error=cast-qual
 
-# warning caused by dcd_nrf5x.c due to include of usbd.h and re-declare of dcd_int_handler()
-CFLAGS += -Wno-error=redundant-decls
-
 # All source paths should be relative to the top level.
 LD_FILE ?= hw/bsp/nrf/boards/$(BOARD)/nrf52840_s140_v6.ld
 
diff --git a/src/class/msc/msc_device.c b/src/class/msc/msc_device.c
index 33dd4ac3..00b0a1d0 100644
--- a/src/class/msc/msc_device.c
+++ b/src/class/msc/msc_device.c
@@ -28,9 +28,9 @@
 
 #if (CFG_TUD_ENABLED && CFG_TUD_MSC)
 
+#include "device/dcd.h"         // for faking dcd_event_xfer_complete
 #include "device/usbd.h"
 #include "device/usbd_pvt.h"
-#include "device/dcd.h"         // for faking dcd_event_xfer_complete
 
 #include "msc_device.h"
 
diff --git a/src/device/dcd.h b/src/device/dcd.h
index 6b99734f..c1780f65 100644
--- a/src/device/dcd.h
+++ b/src/device/dcd.h
@@ -110,14 +110,7 @@ typedef struct TU_ATTR_ALIGNED(4)
 void dcd_init       (uint8_t rhport);
 
 // Interrupt Handler
-#if __GNUC__ && !defined(__ARMCC_VERSION)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wredundant-decls"
-#endif
 void dcd_int_handler(uint8_t rhport);
-#if __GNUC__ && !defined(__ARMCC_VERSION)
-#pragma GCC diagnostic pop
-#endif
 
 // Enable device interrupt
 void dcd_int_enable (uint8_t rhport);
diff --git a/src/device/usbd.c b/src/device/usbd.c
index fa894acc..b2053174 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -28,12 +28,12 @@
 
 #if CFG_TUD_ENABLED
 
+#include "device/dcd.h"
 #include "tusb.h"
 #include "common/tusb_private.h"
 
 #include "device/usbd.h"
 #include "device/usbd_pvt.h"
-#include "device/dcd.h"
 
 //--------------------------------------------------------------------+
 // USBD Configuration
diff --git a/src/device/usbd.h b/src/device/usbd.h
index 964cfb99..17b4d927 100644
--- a/src/device/usbd.h
+++ b/src/device/usbd.h
@@ -58,8 +58,11 @@ void tud_task (void)
 // Check if there is pending events need processing by tud_task()
 bool tud_task_event_ready(void);
 
-// Interrupt handler, name alias to DCD
+#ifndef _TUSB_DCD_H_
 extern void dcd_int_handler(uint8_t rhport);
+#endif
+
+// Interrupt handler, name alias to DCD
 #define tud_int_handler   dcd_int_handler
 
 // Get current bus speed
diff --git a/src/device/usbd_control.c b/src/device/usbd_control.c
index 94a952df..0995ef66 100644
--- a/src/device/usbd_control.c
+++ b/src/device/usbd_control.c
@@ -28,9 +28,9 @@
 
 #if CFG_TUD_ENABLED
 
+#include "dcd.h"
 #include "tusb.h"
 #include "device/usbd_pvt.h"
-#include "dcd.h"
 
 #if CFG_TUSB_DEBUG >= 2
 extern void usbd_driver_print_control_complete_name(usbd_control_xfer_cb_t callback);
diff --git a/src/host/hub.c b/src/host/hub.c
index 5c0fd916..3400b154 100644
--- a/src/host/hub.c
+++ b/src/host/hub.c
@@ -28,6 +28,7 @@
 
 #if (CFG_TUH_ENABLED && CFG_TUH_HUB)
 
+#include "hcd.h"
 #include "usbh.h"
 #include "usbh_classdriver.h"
 #include "hub.h"
diff --git a/src/host/usbh.c b/src/host/usbh.c
index 4807d20b..4c9b0b1b 100644
--- a/src/host/usbh.c
+++ b/src/host/usbh.c
@@ -28,10 +28,9 @@
 
 #if CFG_TUH_ENABLED
 
+#include "host/hcd.h"
 #include "tusb.h"
 #include "common/tusb_private.h"
-
-#include "host/usbh.h"
 #include "host/usbh_classdriver.h"
 #include "hub.h"
 
diff --git a/src/host/usbh.h b/src/host/usbh.h
index 347c75b8..560a1ea2 100644
--- a/src/host/usbh.h
+++ b/src/host/usbh.h
@@ -32,7 +32,6 @@
 #endif
 
 #include "common/tusb_common.h"
-#include "hcd.h"
 
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
@@ -115,8 +114,11 @@ void tuh_task(void)
   tuh_task_ext(UINT32_MAX, false);
 }
 
-// Interrupt handler, name alias to HCD
+#ifndef _TUSB_HCD_H_
 extern void hcd_int_handler(uint8_t rhport);
+#endif
+
+// Interrupt handler, name alias to HCD
 #define tuh_int_handler   hcd_int_handler
 
 bool tuh_vid_pid_get(uint8_t daddr, uint16_t* vid, uint16_t* pid);