diff --git a/include/tools_share/sptool.h b/include/tools_share/sptool.h
index 67a2cf0..53668e0 100644
--- a/include/tools_share/sptool.h
+++ b/include/tools_share/sptool.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,21 +9,17 @@
 
 #include <stdint.h>
 
-/* Header for a secure partition package. There is one per package. */
-struct sp_pkg_header {
-	uint64_t version;
-	uint64_t number_of_sp;
-};
+/* 4 Byte magic name "SPKG" */
+#define SECURE_PARTITION_MAGIC		0x474B5053
 
-/*
- * Entry descriptor in a secure partition package. Each entry comprises a
- * secure partition and its resource description.
- */
-struct sp_pkg_entry {
-	uint64_t sp_offset;
-	uint64_t sp_size;
-	uint64_t rd_offset;
-	uint64_t rd_size;
+/* Header for a secure partition package. */
+struct sp_pkg_header {
+	uint32_t magic;
+	uint32_t version;
+	uint32_t pm_offset;
+	uint32_t pm_size;
+	uint32_t img_offset;
+	uint32_t img_size;
 };
 
 #endif /* SPTOOL_H */