diff --git a/plat/st/stm32mp1/platform.mk b/plat/st/stm32mp1/platform.mk
index 127e318..a903a16 100644
--- a/plat/st/stm32mp1/platform.mk
+++ b/plat/st/stm32mp1/platform.mk
@@ -65,6 +65,10 @@
 # STM32 image header version v1.0
 STM32_HEADER_VERSION_MAJOR:=	1
 STM32_HEADER_VERSION_MINOR:=	0
+
+# Add OP-TEE reserved shared memory area in mapping
+STM32MP15_OPTEE_RSV_SHM	:=	1
+$(eval $(call add_defines,STM32MP15_OPTEE_RSV_SHM))
 endif
 
 # STM32 image header binary type for BL2
diff --git a/plat/st/stm32mp1/stm32mp1_fip_def.h b/plat/st/stm32mp1/stm32mp1_fip_def.h
index 2076175..82e53db 100644
--- a/plat/st/stm32mp1/stm32mp1_fip_def.h
+++ b/plat/st/stm32mp1/stm32mp1_fip_def.h
@@ -7,8 +7,13 @@
 #ifndef STM32MP1_FIP_DEF_H
 #define STM32MP1_FIP_DEF_H
 
+#if STM32MP15_OPTEE_RSV_SHM
 #define STM32MP_DDR_S_SIZE		U(0x01E00000)	/* 30 MB */
 #define STM32MP_DDR_SHMEM_SIZE		U(0x00200000)	/* 2 MB */
+#else
+#define STM32MP_DDR_S_SIZE		U(0x02000000)	/* 32 MB */
+#define STM32MP_DDR_SHMEM_SIZE		U(0)		/* empty */
+#endif
 
 #if STM32MP13
 #define STM32MP_BL2_RO_SIZE		U(0x00015000)	/* 84 KB */
diff --git a/plat/st/stm32mp1/stm32mp1_stm32image_def.h b/plat/st/stm32mp1/stm32mp1_stm32image_def.h
index 8efa342..6260cb9 100644
--- a/plat/st/stm32mp1/stm32mp1_stm32image_def.h
+++ b/plat/st/stm32mp1/stm32mp1_stm32image_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2021, STMicroelectronics - All Rights Reserved
+ * Copyright (C) 2021-2022, STMicroelectronics - All Rights Reserved
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -8,9 +8,14 @@
 #define STM32MP1_STM32IMAGE_DEF_H
 
 #ifdef AARCH32_SP_OPTEE
+#if STM32MP15_OPTEE_RSV_SHM
 #define STM32MP_DDR_S_SIZE		U(0x01E00000)	/* 30 MB */
 #define STM32MP_DDR_SHMEM_SIZE		U(0x00200000)	/* 2 MB */
 #else
+#define STM32MP_DDR_S_SIZE		U(0x02000000)	/* 32 MB */
+#define STM32MP_DDR_SHMEM_SIZE		U(0)		/* empty */
+#endif
+#else
 #define STM32MP_DDR_S_SIZE		U(0)
 #define STM32MP_DDR_SHMEM_SIZE		U(0)
 #endif