diff --git a/plat/st/common/stm32mp_common.c b/plat/st/common/stm32mp_common.c
index d3de1e14f..aa87c5d6b 100644
--- a/plat/st/common/stm32mp_common.c
+++ b/plat/st/common/stm32mp_common.c
@@ -105,7 +105,7 @@ int stm32mp_map_ddr_non_cacheable(void)
 {
 	return  mmap_add_dynamic_region(STM32MP_DDR_BASE, STM32MP_DDR_BASE,
 					STM32MP_DDR_MAX_SIZE,
-					MT_NON_CACHEABLE | MT_RW | MT_NS);
+					MT_NON_CACHEABLE | MT_RW | MT_SECURE);
 }
 
 int stm32mp_unmap_ddr(void)
diff --git a/plat/st/stm32mp1/bl2_plat_setup.c b/plat/st/stm32mp1/bl2_plat_setup.c
index 91073b89d..3e179fbbf 100644
--- a/plat/st/stm32mp1/bl2_plat_setup.c
+++ b/plat/st/stm32mp1/bl2_plat_setup.c
@@ -132,7 +132,6 @@ void bl2_el3_early_platform_setup(u_register_t arg0,
 void bl2_platform_setup(void)
 {
 	int ret;
-	uint32_t ddr_ns_size;
 
 	if (dt_pmic_status() > 0) {
 		initialize_pmic();
@@ -144,24 +143,16 @@ void bl2_platform_setup(void)
 		panic();
 	}
 
-	ddr_ns_size = stm32mp_get_ddr_ns_size();
-	assert(ddr_ns_size > 0U);
-
-	/* Map non secure DDR for BL33 load, now with cacheable attribute */
+	/* Map DDR for binary load, now with cacheable attribute */
 	ret = mmap_add_dynamic_region(STM32MP_DDR_BASE, STM32MP_DDR_BASE,
-				      ddr_ns_size, MT_MEMORY | MT_RW | MT_NS);
-	assert(ret == 0);
+				      STM32MP_DDR_MAX_SIZE, MT_MEMORY | MT_RW | MT_SECURE);
+	if (ret < 0) {
+		ERROR("DDR mapping: error %d\n", ret);
+		panic();
+	}
 
 #ifdef AARCH32_SP_OPTEE
 	INFO("BL2 runs OP-TEE setup\n");
-
-	/* Map secure DDR for OP-TEE paged area */
-	ret = mmap_add_dynamic_region(STM32MP_DDR_BASE + ddr_ns_size,
-				      STM32MP_DDR_BASE + ddr_ns_size,
-				      STM32MP_DDR_S_SIZE,
-				      MT_MEMORY | MT_RW | MT_SECURE);
-	assert(ret == 0);
-
 	/* Initialize tzc400 after DDR initialization */
 	stm32mp1_security_setup();
 #else
diff --git a/plat/st/stm32mp1/stm32mp1_security.c b/plat/st/stm32mp1/stm32mp1_security.c
index 6dbf6f8c4..2ee5f4a85 100644
--- a/plat/st/stm32mp1/stm32mp1_security.c
+++ b/plat/st/stm32mp1/stm32mp1_security.c
@@ -29,11 +29,14 @@
 
 static unsigned int region_nb;
 
-static void init_tzc400_begin(void)
+static void init_tzc400_begin(unsigned int region0_attr)
 {
 	tzc400_init(STM32MP1_TZC_BASE);
 	tzc400_disable_filters();
 
+	/* Region 0 set to cover all DRAM at 0xC000_0000 */
+	tzc400_configure_region0(region0_attr, 0);
+
 	region_nb = 1U;
 }
 
@@ -76,7 +79,7 @@ static void init_tzc400(void)
 	unsigned long long ddr_ns_top = ddr_base + (ddr_ns_size - 1U);
 	unsigned long long ddr_top __unused;
 
-	init_tzc400_begin();
+	init_tzc400_begin(TZC_REGION_S_NONE);
 
 	/*
 	 * Region 1 set to cover all non-secure DRAM at 0xC000_0000. Apply the
@@ -118,16 +121,8 @@ static void early_init_tzc400(void)
 	stm32mp_clk_enable(TZC1);
 	stm32mp_clk_enable(TZC2);
 
-	init_tzc400_begin();
-
-	/* Region 1 set to cover Non-Secure DRAM at 0xC000_0000 */
-	tzc400_configure_region(STM32MP1_FILTER_BIT_ALL, 1,
-				STM32MP_DDR_BASE,
-				STM32MP_DDR_BASE +
-				(STM32MP_DDR_MAX_SIZE - 1U),
-				TZC_REGION_S_NONE,
-				TZC_REGION_ACCESS_RDWR(STM32MP1_TZC_A7_ID) |
-				TZC_REGION_ACCESS_RDWR(STM32MP1_TZC_SDMMC_ID));
+	/* Region 0 set to cover all DRAM secure at 0xC000_0000 */
+	init_tzc400_begin(TZC_REGION_S_RDWR);
 
 	/* Raise an exception if a NS device tries to access secure memory */
 	init_tzc400_end(TZC_ACTION_ERR);