diff --git a/platform/source/mbed_application.c b/platform/source/mbed_application.c
index 5cd70c6c4d..b52dfe6a31 100644
--- a/platform/source/mbed_application.c
+++ b/platform/source/mbed_application.c
@@ -71,17 +71,6 @@ void mbed_start_application(uintptr_t address)
     powerdown_scb(address);
     mbed_mpu_manager_deinit();
 
-#ifdef MBED_DEBUG
-    // Configs to make debugging easier
-#ifdef SCnSCB_ACTLR_DISDEFWBUF_Msk
-    // Disable write buffer to make BusFaults (eg write to ROM via NULL pointer) precise.
-    // Possible on Cortex-M3 and M4, not on M0, M7 or M33.
-    // Would be less necessary if ROM was write-protected in MPU to give a
-    // precise MemManage exception.
-    SCnSCB->ACTLR |= SCnSCB_ACTLR_DISDEFWBUF_Msk;
-#endif
-#endif
-
     sp = *((void **)address + 0);
     pc = *((void **)address + 1);
     start_new_application(sp, pc);
diff --git a/platform/source/mbed_sdk_boot.c b/platform/source/mbed_sdk_boot.c
index fe19053547..7234578925 100644
--- a/platform/source/mbed_sdk_boot.c
+++ b/platform/source/mbed_sdk_boot.c
@@ -77,6 +77,16 @@ void mbed_copy_nvic(void)
 
 void mbed_init(void)
 {
+#ifdef MBED_DEBUG
+    // Configs to make debugging easier
+#ifdef SCnSCB_ACTLR_DISDEFWBUF_Msk
+    // Disable write buffer to make BusFaults (eg write to ROM via NULL pointer) precise.
+    // Possible on Cortex-M3 and M4, not on M0, M7 or M33.
+    // Would be less necessary if ROM was write-protected in MPU to give a
+    // precise MemManage exception.
+    SCnSCB->ACTLR |= SCnSCB_ACTLR_DISDEFWBUF_Msk;
+#endif
+#endif
     mbed_copy_nvic();
     mbed_sdk_init();
 #if DEVICE_USTICKER && MBED_CONF_TARGET_INIT_US_TICKER_AT_BOOT
diff --git a/rtos/source/TARGET_CORTEX/mbed_boot.c b/rtos/source/TARGET_CORTEX/mbed_boot.c
index b4257f88db..d63e12c014 100644
--- a/rtos/source/TARGET_CORTEX/mbed_boot.c
+++ b/rtos/source/TARGET_CORTEX/mbed_boot.c
@@ -73,6 +73,16 @@ uint32_t mbed_stack_isr_size = 0;
 
 void mbed_init(void)
 {
+#ifdef MBED_DEBUG
+    // Configs to make debugging easier
+#ifdef SCnSCB_ACTLR_DISDEFWBUF_Msk
+    // Disable write buffer to make BusFaults (eg write to ROM via NULL pointer) precise.
+    // Possible on Cortex-M3 and M4, not on M0, M7 or M33.
+    // Would be less necessary if ROM was write-protected in MPU to give a
+    // precise MemManage exception.
+    SCnSCB->ACTLR |= SCnSCB_ACTLR_DISDEFWBUF_Msk;
+#endif
+#endif
     mbed_mpu_manager_init();
     mbed_cpy_nvic();
     mbed_sdk_init();