diff --git a/docs/design/firmware-design.rst b/docs/design/firmware-design.rst
index 8297dc7..8e9dc38 100644
--- a/docs/design/firmware-design.rst
+++ b/docs/design/firmware-design.rst
@@ -1859,7 +1859,7 @@
                |   BL2    |  <<<<<<<<<<<<<  |                |
                |----------|  <<<<<<<<<<<<<  |----------------|
                | SCP_BL2  |  <<<<<<<<<<<<<  | BL31 PROGBITS  |
-               |----------|  <<<<<<<<<<<<<  |----------------|
+               |          |  <<<<<<<<<<<<<  |----------------|
                |          |  <<<<<<<<<<<<<  |     BL32       |
                |          |                 +----------------+
                |          |
@@ -1896,7 +1896,7 @@
                |   BL2    |  <<<<<<<<<<<<<  |                |
                |----------|  <<<<<<<<<<<<<  |----------------|
                | SCP_BL2  |  <<<<<<<<<<<<<  | BL31 PROGBITS  |
-               |----------|                 +----------------+
+               |          |                 +----------------+
     0x04001000 +----------+
                |   MHU    |
     0x04000000 +----------+
diff --git a/plat/arm/board/juno/include/platform_def.h b/plat/arm/board/juno/include/platform_def.h
index cfac801..b446395 100644
--- a/plat/arm/board/juno/include/platform_def.h
+++ b/plat/arm/board/juno/include/platform_def.h
@@ -249,16 +249,12 @@
 #endif
 
 /*
- * PLAT_CSS_MAX_SCP_BL2_SIZE is calculated using the current
- * SCP_BL2 size plus a little space for growth.
+ * SCP_BL2 uses up whatever remaining space is available as it is loaded before
+ * anything else in this memory region and is handed over to the SCP before
+ * BL31 is loaded over the top.
  */
-#define PLAT_CSS_MAX_SCP_BL2_SIZE	UL(0x14000)
-
-/*
- * PLAT_CSS_MAX_SCP_BL2U_SIZE is calculated using the current
- * SCP_BL2U size plus a little space for growth.
- */
-#define PLAT_CSS_MAX_SCP_BL2U_SIZE	UL(0x14000)
+#define PLAT_CSS_MAX_SCP_BL2_SIZE	(SCP_BL2_LIMIT - ARM_TB_FW_CONFIG_LIMIT)
+#define PLAT_CSS_MAX_SCP_BL2U_SIZE	PLAT_CSS_MAX_SCP_BL2_SIZE
 
 #define PLAT_ARM_G1S_IRQ_PROPS(grp) \
 	CSS_G1S_IRQ_PROPS(grp), \
diff --git a/plat/arm/css/sgm/include/sgm_base_platform_def.h b/plat/arm/css/sgm/include/sgm_base_platform_def.h
index 90511ac..0ac0c2b 100644
--- a/plat/arm/css/sgm/include/sgm_base_platform_def.h
+++ b/plat/arm/css/sgm/include/sgm_base_platform_def.h
@@ -133,16 +133,12 @@
 #endif
 
 /*
- * PLAT_CSS_MAX_SCP_BL2_SIZE is calculated using the current
- * SCP_BL2 size plus a little space for growth.
+ * SCP_BL2 uses up whatever remaining space is available as it is loaded before
+ * anything else in this memory region and is handed over to the SCP before
+ * BL31 is loaded over the top.
  */
-#define PLAT_CSS_MAX_SCP_BL2_SIZE	0x15000
-
-/*
- * PLAT_CSS_MAX_SCP_BL2U_SIZE is calculated using the current
- * SCP_BL2U size plus a little space for growth.
- */
-#define PLAT_CSS_MAX_SCP_BL2U_SIZE	0x15000
+#define PLAT_CSS_MAX_SCP_BL2_SIZE	(SCP_BL2_LIMIT - ARM_TB_FW_CONFIG_LIMIT)
+#define PLAT_CSS_MAX_SCP_BL2U_SIZE	PLAT_CSS_MAX_SCP_BL2_SIZE
 
 /*
  * Most platform porting definitions provided by included headers