diff --git a/docs/components/romlib-design.rst b/docs/components/romlib-design.rst
index d8bc89c..e0a028e 100644
--- a/docs/components/romlib-design.rst
+++ b/docs/components/romlib-design.rst
@@ -111,6 +111,21 @@
 
 BL image --> function
 
+Memory impact
+~~~~~~~~~~~~~
+
+Using library at ROM will modify the memory layout of the BL images:
+- The ROM library needs a page aligned RAM section to hold the RW data. This
+   section is defined by the ROMLIB_RW_BASE and ROMLIB_RW_END macros.
+   On Arm platforms a section of 1 page (0x1000) is allocated at the top of SRAM.
+   This will have for effect to shift down all the BL images by 1 page.
+- Depending on the functions moved to the ROM library, the size of the BL images
+   will be reduced.
+   For example: moving MbedTLS function into the ROM library reduces BL1 and
+   BL2, but not BL31.
+- This change in BL images size can be taken into consideration to optimize the
+   memory layout when defining the BLx_BASE macros.
+
 Build library at ROM
 ~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/plat/arm/board/fvp/include/platform_def.h b/plat/arm/board/fvp/include/platform_def.h
index 4f26277..98dd0a9 100644
--- a/plat/arm/board/fvp/include/platform_def.h
+++ b/plat/arm/board/fvp/include/platform_def.h
@@ -94,9 +94,11 @@
 #if USE_ROMLIB
 #define PLAT_ARM_MAX_ROMLIB_RW_SIZE	UL(0x1000)
 #define PLAT_ARM_MAX_ROMLIB_RO_SIZE	UL(0xe000)
+#define FVP_BL2_ROMLIB_OPTIMIZATION UL(0x6000)
 #else
 #define PLAT_ARM_MAX_ROMLIB_RW_SIZE	UL(0)
 #define PLAT_ARM_MAX_ROMLIB_RO_SIZE	UL(0)
+#define FVP_BL2_ROMLIB_OPTIMIZATION UL(0)
 #endif
 
 /*
@@ -104,9 +106,9 @@
  * little space for growth.
  */
 #if TRUSTED_BOARD_BOOT
-# define PLAT_ARM_MAX_BL2_SIZE		UL(0x1D000)
+# define PLAT_ARM_MAX_BL2_SIZE	(UL(0x1D000) - FVP_BL2_ROMLIB_OPTIMIZATION)
 #else
-# define PLAT_ARM_MAX_BL2_SIZE		UL(0x11000)
+# define PLAT_ARM_MAX_BL2_SIZE	(UL(0x11000) - FVP_BL2_ROMLIB_OPTIMIZATION)
 #endif
 
 /*
diff --git a/plat/arm/board/juno/include/platform_def.h b/plat/arm/board/juno/include/platform_def.h
index 83aeeb4..16bb33d 100644
--- a/plat/arm/board/juno/include/platform_def.h
+++ b/plat/arm/board/juno/include/platform_def.h
@@ -60,9 +60,11 @@
 #if USE_ROMLIB
 #define PLAT_ARM_MAX_ROMLIB_RW_SIZE	UL(0x1000)
 #define PLAT_ARM_MAX_ROMLIB_RO_SIZE	UL(0xe000)
+#define JUNO_BL2_ROMLIB_OPTIMIZATION UL(0x8000)
 #else
 #define PLAT_ARM_MAX_ROMLIB_RW_SIZE	UL(0)
 #define PLAT_ARM_MAX_ROMLIB_RO_SIZE	UL(0)
+#define JUNO_BL2_ROMLIB_OPTIMIZATION UL(0)
 #endif
 
 /*
@@ -127,14 +129,14 @@
  */
 #if TRUSTED_BOARD_BOOT
 #if TF_MBEDTLS_KEY_ALG_ID == TF_MBEDTLS_RSA_AND_ECDSA
-# define PLAT_ARM_MAX_BL2_SIZE		UL(0x1F000)
+# define PLAT_ARM_MAX_BL2_SIZE	(UL(0x1F000) - JUNO_BL2_ROMLIB_OPTIMIZATION)
 #elif TF_MBEDTLS_KEY_ALG_ID == TF_MBEDTLS_ECDSA
-# define PLAT_ARM_MAX_BL2_SIZE		UL(0x1D000)
+# define PLAT_ARM_MAX_BL2_SIZE	(UL(0x1D000) - JUNO_BL2_ROMLIB_OPTIMIZATION)
 #else
-# define PLAT_ARM_MAX_BL2_SIZE		UL(0x1D000)
+# define PLAT_ARM_MAX_BL2_SIZE	(UL(0x1D000) - JUNO_BL2_ROMLIB_OPTIMIZATION)
 #endif
 #else
-# define PLAT_ARM_MAX_BL2_SIZE		UL(0xF000)
+# define PLAT_ARM_MAX_BL2_SIZE	(UL(0xF000) - JUNO_BL2_ROMLIB_OPTIMIZATION)
 #endif
 
 /*