diff --git a/include/drivers/measured_boot/event_log/event_log.h b/include/drivers/measured_boot/event_log/event_log.h
index 78712af..a687d41 100644
--- a/include/drivers/measured_boot/event_log/event_log.h
+++ b/include/drivers/measured_boot/event_log/event_log.h
@@ -38,7 +38,7 @@
 /* Number of hashing algorithms supported */
 #define HASH_ALG_COUNT		1U
 
-#define EVLOG_INVALID_ID	MAX_NUMBER_IDS
+#define EVLOG_INVALID_ID	UINT32_MAX
 
 #define MEMBER_SIZE(type, member) sizeof(((type *)0)->member)
 
diff --git a/include/plat/common/common_def.h b/include/plat/common/common_def.h
index 14ae603..632f122 100644
--- a/include/plat/common/common_def.h
+++ b/include/plat/common/common_def.h
@@ -85,4 +85,12 @@
 #endif /* BL2_IN_XIP_MEM */
 #endif /* SEPARATE_CODE_AND_RODATA */
 
+#if MEASURED_BOOT
+/*
+ * Start critical data Ids from 2^32/2 reserving Ids from 0 to (2^32/2 - 1)
+ * for Images, It is a critical data Id base for all platforms.
+ */
+#define CRITICAL_DATA_ID_BASE	U(0x80000000)
+#endif /* MEASURED_BOOT */
+
 #endif /* COMMON_DEF_H */
diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index 3fa63f5..9a61b50 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -124,12 +124,22 @@
 
 #if MEASURED_BOOT
 int plat_mboot_measure_image(unsigned int image_id, image_info_t *image_data);
+int plat_mboot_measure_critical_data(unsigned int critical_data_id,
+				     const void *base,
+				     size_t size);
 #else
 static inline int plat_mboot_measure_image(unsigned int image_id __unused,
 					   image_info_t *image_data __unused)
 {
 	return 0;
 }
+static inline int plat_mboot_measure_critical_data(
+					unsigned int critical_data_id __unused,
+					const void *base __unused,
+					size_t size __unused)
+{
+	return 0;
+}
 #endif /* MEASURED_BOOT */
 
 /*******************************************************************************