diff --git a/Source/portable/GCC/RX600/port.c b/Source/portable/GCC/RX600/port.c
index 284fa56a1..5f0ef46fd 100644
--- a/Source/portable/GCC/RX600/port.c
+++ b/Source/portable/GCC/RX600/port.c
@@ -113,7 +113,7 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
 {
 	/* R0 is not included as it is the stack pointer. */
 	
-	*pxTopOfStack = 0xdeadbeef;
+	*pxTopOfStack = 0x00;
 	pxTopOfStack--;
  	*pxTopOfStack = portINITIAL_PSW;
 	pxTopOfStack--;
diff --git a/Source/portable/IAR/RX600/port.c b/Source/portable/IAR/RX600/port.c
index e70dbeef2..4aeb7130b 100644
--- a/Source/portable/IAR/RX600/port.c
+++ b/Source/portable/IAR/RX600/port.c
@@ -99,7 +99,7 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
 {
 	/* R0 is not included as it is the stack pointer. */
 	
-	*pxTopOfStack = 0xdeadbeef;
+	*pxTopOfStack = 0x00;
 	pxTopOfStack--;
  	*pxTopOfStack = portINITIAL_PSW;
 	pxTopOfStack--;
diff --git a/Source/portable/Renesas/RX200/port.c b/Source/portable/Renesas/RX200/port.c
index bfb6cc3f6..4aa61409e 100644
--- a/Source/portable/Renesas/RX200/port.c
+++ b/Source/portable/Renesas/RX200/port.c
@@ -118,9 +118,9 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
 {
 	/* R0 is not included as it is the stack pointer. */
 	
-	*pxTopOfStack = 0xdeadbeef;
+	*pxTopOfStack = 0x00;
 	pxTopOfStack--;
-    *pxTopOfStack = 0xdeadbeef;
+    *pxTopOfStack = 0x00;
 	pxTopOfStack--;
  	*pxTopOfStack = portINITIAL_PSW;
 	pxTopOfStack--;
diff --git a/Source/portable/Renesas/RX600/port.c b/Source/portable/Renesas/RX600/port.c
index b48617517..eca770535 100644
--- a/Source/portable/Renesas/RX600/port.c
+++ b/Source/portable/Renesas/RX600/port.c
@@ -119,7 +119,7 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
 {
 	/* R0 is not included as it is the stack pointer. */
 	
-	*pxTopOfStack = 0xdeadbeef;
+	*pxTopOfStack = 0x00;
 	pxTopOfStack--;
  	*pxTopOfStack = portINITIAL_PSW;
 	pxTopOfStack--;