diff --git a/arch/sh/src/m16c/m16c_initialstate.c b/arch/sh/src/m16c/m16c_initialstate.c
index e4c55678858..1893672790a 100644
--- a/arch/sh/src/m16c/m16c_initialstate.c
+++ b/arch/sh/src/m16c/m16c_initialstate.c
@@ -40,7 +40,10 @@
 #include <nuttx/config.h>
 #include <sys/types.h>
 #include <string.h>
+
 #include <nuttx/arch.h>
+#include <arch/board/board.h>
+
 #include "up_internal.h"
 #include "up_arch.h"
 
@@ -48,8 +51,6 @@
  * Preprocessor Definitions
  ****************************************************************************/
 
-#define M16C_DEFAULT_IPL   0     /* Default M16C Interrupt priority level */
-
 /****************************************************************************
  * Private Data
  ****************************************************************************/
diff --git a/arch/sh/src/m16c/m16c_timerisr.c b/arch/sh/src/m16c/m16c_timerisr.c
index 962166071be..3cc63271902 100644
--- a/arch/sh/src/m16c/m16c_timerisr.c
+++ b/arch/sh/src/m16c/m16c_timerisr.c
@@ -41,7 +41,9 @@
 #include <sys/types.h>
 #include <time.h>
 #include <debug.h>
+
 #include <nuttx/arch.h>
+#include <arch/board/board.h>
 
 #include "clock_internal.h"
 #include "up_internal.h"
diff --git a/arch/sh/src/m16c/m16c_vectors.S b/arch/sh/src/m16c/m16c_vectors.S
index 2ffa50154d9..17f47f56039 100644
--- a/arch/sh/src/m16c/m16c_vectors.S
+++ b/arch/sh/src/m16c/m16c_vectors.S
@@ -346,6 +346,13 @@ _m16c_commonvector:
 	fclr	u				/* Back to interrupt stack */
 	push.w	r0				/* Save user sp on isp */
 
+/* Allow nested interrupts */
+
+#ifdef M16C_INTERRUPT_IPL
+	fset	i				/* Enable interrupts */
+	ldipl	#M16C_INTERRUPT_IPL		/* Set interrupt level */
+#endif
+
 /* Then call _up_doirq with r1=IRQ number, r2=address of context info.  At this
  * point, the interrupt stack holds the address of the last byte of the context
  * info array
@@ -354,6 +361,10 @@ _m16c_commonvector:
  	stc	isp, r2				/* R2 = address of base of context info */
 	jsr.a	_up_doirq
 
+#ifdef M16C_INTERRUPT_IPL
+	fclr	i				/* Disable interrupts */
+#endif
+
 /* Upon return, r0 will hold address of the base of the new context info structure
  * use for return.  Most of the time this will be the same as the address passed to
  * to _up_doirg above, but will differ if a context switch occurs during interrupt