diff --git a/boot/startup/src/arch/cortex_m0/cortex_m0_startup.s b/boot/startup/src/arch/cortex_m0/cortex_m0_startup.s
index eab5591468..fd590791a0 100644
--- a/boot/startup/src/arch/cortex_m0/cortex_m0_startup.s
+++ b/boot/startup/src/arch/cortex_m0/cortex_m0_startup.s
@@ -17,6 +17,8 @@
  * under the License.
  */
 
+#include "syscfg/syscfg.h"
+
     .syntax unified
     .arch   armv6-m
 
@@ -64,6 +66,15 @@ Reset_Handler:
 
 .L_zero_table_done:
 
+#if MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r0, =MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r2, =__StackLimit
+    mov     r1, sp
+0:  stm     r2!, {r0}
+    cmp     r2, r1
+    blt     0b
+#endif
+
     ldr     r0, =__HeapBase
     ldr     r1, =__HeapLimit
     bl      _sbrkInit
diff --git a/boot/startup/src/arch/cortex_m3/cortex_m3_startup.s b/boot/startup/src/arch/cortex_m3/cortex_m3_startup.s
index 03f77f7799..4e6b20eeaf 100644
--- a/boot/startup/src/arch/cortex_m3/cortex_m3_startup.s
+++ b/boot/startup/src/arch/cortex_m3/cortex_m3_startup.s
@@ -17,6 +17,8 @@
  * under the License.
  */
 
+#include "syscfg/syscfg.h"
+
     .syntax unified
     .arch   armv7-m
 
@@ -67,6 +69,15 @@ Reset_Handler:
     b       .L_for_each_zero_region
 .L_zero_table_done:
 
+#if MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r0, =MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r2, =__StackLimit
+    mov     r1, sp
+0:  stm     r2!, {r0}
+    cmp     r2, r1
+    blt     0b
+#endif
+
     ldr     r0, =__HeapBase
     ldr     r1, =__HeapLimit
     bl      _sbrkInit
diff --git a/boot/startup/src/arch/cortex_m33/cortex_m33_startup.s b/boot/startup/src/arch/cortex_m33/cortex_m33_startup.s
index 471927f42b..27f995c913 100644
--- a/boot/startup/src/arch/cortex_m33/cortex_m33_startup.s
+++ b/boot/startup/src/arch/cortex_m33/cortex_m33_startup.s
@@ -17,6 +17,8 @@
  * under the License.
  */
 
+#include "syscfg/syscfg.h"
+
     .syntax unified
     .arch   armv7-m
 
@@ -70,6 +72,15 @@ Reset_Handler:
     b       .L_for_each_zero_region
 .L_zero_table_done:
 
+#if MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r0, =MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r2, =__StackLimit
+    mov     r1, sp
+0:  stm     r2!, {r0}
+    cmp     r2, r1
+    blt     0b
+#endif
+
     ldr     r0, =__HeapBase
     ldr     r1, =__HeapLimit
     bl      _sbrkInit
diff --git a/boot/startup/src/arch/cortex_m4/cortex_m4_startup.s b/boot/startup/src/arch/cortex_m4/cortex_m4_startup.s
index 03f77f7799..4e6b20eeaf 100644
--- a/boot/startup/src/arch/cortex_m4/cortex_m4_startup.s
+++ b/boot/startup/src/arch/cortex_m4/cortex_m4_startup.s
@@ -17,6 +17,8 @@
  * under the License.
  */
 
+#include "syscfg/syscfg.h"
+
     .syntax unified
     .arch   armv7-m
 
@@ -67,6 +69,15 @@ Reset_Handler:
     b       .L_for_each_zero_region
 .L_zero_table_done:
 
+#if MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r0, =MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r2, =__StackLimit
+    mov     r1, sp
+0:  stm     r2!, {r0}
+    cmp     r2, r1
+    blt     0b
+#endif
+
     ldr     r0, =__HeapBase
     ldr     r1, =__HeapLimit
     bl      _sbrkInit
diff --git a/boot/startup/src/arch/cortex_m7/cortex_m7_startup.s b/boot/startup/src/arch/cortex_m7/cortex_m7_startup.s
index 03f77f7799..4e6b20eeaf 100644
--- a/boot/startup/src/arch/cortex_m7/cortex_m7_startup.s
+++ b/boot/startup/src/arch/cortex_m7/cortex_m7_startup.s
@@ -17,6 +17,8 @@
  * under the License.
  */
 
+#include "syscfg/syscfg.h"
+
     .syntax unified
     .arch   armv7-m
 
@@ -67,6 +69,15 @@ Reset_Handler:
     b       .L_for_each_zero_region
 .L_zero_table_done:
 
+#if MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r0, =MYNEWT_VAL_MAIN_STACK_FILL
+    ldr     r2, =__StackLimit
+    mov     r1, sp
+0:  stm     r2!, {r0}
+    cmp     r2, r1
+    blt     0b
+#endif
+
     ldr     r0, =__HeapBase
     ldr     r1, =__HeapLimit
     bl      _sbrkInit
diff --git a/boot/startup/syscfg.yml b/boot/startup/syscfg.yml
index 92d00328ab..d416443f28 100644
--- a/boot/startup/syscfg.yml
+++ b/boot/startup/syscfg.yml
@@ -34,6 +34,11 @@ syscfg.defs:
             For bootloader it's main stack, for application this stack is used by interrupts
             and exceptions.
         value: 768
+    MAIN_STACK_FILL:
+        description: >
+            Fill main stack (interrupt stack) with pattern on startup.
+            If not 0, value will be used as a pattern.
+        value: 0
     INCLUDE_IMAGE_HEADER:
         description: Add image header to generated executable.
         value: 1