diff --git a/arch/arm/src/lc823450/Make.defs b/arch/arm/src/lc823450/Make.defs
index 6fbf42aef2..d03f95acc6 100644
--- a/arch/arm/src/lc823450/Make.defs
+++ b/arch/arm/src/lc823450/Make.defs
@@ -63,7 +63,7 @@ CMN_CSRCS += up_ramvec_initialize.c up_ramvec_attach.c
 endif
 
 ifeq ($(CONFIG_BUILD_PROTECTED),y)
-CMN_CSRCS += up_mpu.c up_task_start.c up_pthread_start.c
+CMN_CSRCS += up_task_start.c up_pthread_start.c
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 CMN_CSRCS += up_signal_dispatch.c
 CMN_UASRCS += up_signal_handler.S
@@ -184,5 +184,9 @@ endif
 
 ifeq ($(CONFIG_BUILD_PROTECTED),y)
 CHIP_CSRCS += lc823450_userspace.c
+endif
+
+ifeq ($(CONFIG_ARM_MPU),y)
+CMN_CSRCS  += up_mpu.c
 CHIP_CSRCS += lc823450_mpuinit2.c
 endif
diff --git a/arch/arm/src/lc823450/lc823450_cpustart.c b/arch/arm/src/lc823450/lc823450_cpustart.c
index 82f857e05c..d3aa51cced 100644
--- a/arch/arm/src/lc823450/lc823450_cpustart.c
+++ b/arch/arm/src/lc823450/lc823450_cpustart.c
@@ -60,6 +60,10 @@
 
 #include "lc823450_syscontrol.h"
 
+#if defined(CONFIG_BUILD_FLAT) && defined(CONFIG_ARM_MPU)
+#  include "lc823450_mpuinit2.h"
+#endif
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -113,6 +117,13 @@ static void cpu1_boot(void)
     {
       putreg32((uint32_t)&_stext, NVIC_VECTAB); /* use CPU0 vectors */
 
+#if defined(CONFIG_BUILD_FLAT) && defined(CONFIG_ARM_MPU)
+      lc823450_mpuinitialize();
+
+      irq_attach(LC823450_IRQ_MEMFAULT, up_memfault, NULL);
+      up_enable_irq(LC823450_IRQ_MEMFAULT);
+#endif
+
       irq_attach(LC823450_IRQ_CTXM3_01, lc823450_pause_handler, NULL);
       up_enable_irq(LC823450_IRQ_CTXM3_01);
     }
diff --git a/arch/arm/src/lc823450/lc823450_irq.c b/arch/arm/src/lc823450/lc823450_irq.c
index 7faf0bded8..a2982c6549 100644
--- a/arch/arm/src/lc823450/lc823450_irq.c
+++ b/arch/arm/src/lc823450/lc823450_irq.c
@@ -547,7 +547,7 @@ void up_irqinitialize(void)
    * Fault handler.
    */
 
-#ifdef CONFIG_ARMV7M_MPU
+#ifdef CONFIG_ARM_MPU
   irq_attach(LC823450_IRQ_MEMFAULT, up_memfault, NULL);
   up_enable_irq(LC823450_IRQ_MEMFAULT);
 #endif
@@ -556,9 +556,6 @@ void up_irqinitialize(void)
 
 #ifdef CONFIG_DEBUG
   irq_attach(LC823450_IRQ_NMI, lc823450_nmi, NULL);
-#ifndef CONFIG_ARMV7M_MPU
-  irq_attach(LC823450_IRQ_MEMFAULT, up_memfault, NULL);
-#endif
   irq_attach(LC823450_IRQ_BUSFAULT, lc823450_busfault, NULL);
   irq_attach(LC823450_IRQ_USAGEFAULT, lc823450_usagefault, NULL);
   irq_attach(LC823450_IRQ_PENDSV, lc823450_pendsv, NULL);
diff --git a/arch/arm/src/lc823450/lc823450_mpuinit2.c b/arch/arm/src/lc823450/lc823450_mpuinit2.c
index 91eb170f06..04ff22d22e 100644
--- a/arch/arm/src/lc823450/lc823450_mpuinit2.c
+++ b/arch/arm/src/lc823450/lc823450_mpuinit2.c
@@ -46,9 +46,10 @@
 #include <nuttx/userspace.h>
 
 #include "mpu.h"
+#include "up_internal.h"
 #include "lc823450_mpuinit2.h"
 
-#if defined(CONFIG_BUILD_PROTECTED) && defined(CONFIG_ARM_MPU)
+#ifdef CONFIG_ARM_MPU
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -85,6 +86,7 @@
 
 void lc823450_mpuinitialize(void)
 {
+#ifdef CONFIG_BUILD_PROTECTED
   uintptr_t datastart = MIN(USERSPACE->us_datastart, USERSPACE->us_bssstart);
   uintptr_t dataend   = MAX(USERSPACE->us_dataend,   USERSPACE->us_bssend);
 
@@ -101,6 +103,19 @@ void lc823450_mpuinitialize(void)
                  USERSPACE->us_textend - USERSPACE->us_textstart);
 
   mpu_user_intsram(datastart, dataend - datastart);
+#endif
+
+#ifdef CONFIG_BUILD_FLAT
+  uint32_t size = (uint32_t)((uint32_t)&_eronly - (uint32_t)&_stext);
+
+  /* 128KB align */
+
+  size = size & 0x20000;
+
+  /* Protect text area in SRAM as privileged flash */
+
+  mpu_priv_flash((uintptr_t)&_stext, size);
+#endif
 
   /* Then enable the MPU */
 
@@ -122,5 +137,5 @@ void lc823450_mpu_uheap(uintptr_t start, size_t size)
   mpu_user_intsram(start, size);
 }
 
-#endif /* CONFIG_BUILD_PROTECTED && CONFIG_ARM_MPU */
+#endif /* CONFIG_ARM_MPU */
 
diff --git a/arch/arm/src/lc823450/lc823450_mpuinit2.h b/arch/arm/src/lc823450/lc823450_mpuinit2.h
index 5252c31e21..8ae7d71a85 100644
--- a/arch/arm/src/lc823450/lc823450_mpuinit2.h
+++ b/arch/arm/src/lc823450/lc823450_mpuinit2.h
@@ -69,7 +69,7 @@
  *
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_PROTECTED
+#ifdef CONFIG_ARM_MPU
 void lc823450_mpuinitialize(void);
 #else
 #  define lc823450_mpuinitialize()
@@ -83,7 +83,7 @@ void lc823450_mpuinitialize(void);
  *
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_PROTECTED
+#ifdef CONFIG_ARM_MPU
 void lc823450_mpu_uheap(uintptr_t start, size_t size);
 #else
 #  define lc823450_mpu_uheap(start,size)
diff --git a/arch/arm/src/lc823450/lc823450_start.c b/arch/arm/src/lc823450/lc823450_start.c
index a424210eb3..a98d21ce89 100644
--- a/arch/arm/src/lc823450/lc823450_start.c
+++ b/arch/arm/src/lc823450/lc823450_start.c
@@ -351,6 +351,9 @@ void __start(void)
 
 #ifdef CONFIG_BUILD_PROTECTED
   lc823450_userspace();
+#endif
+#if defined(CONFIG_BUILD_FLAT) && defined(CONFIG_ARM_MPU)
+  lc823450_mpuinitialize();
 #endif
   showprogress('E');