diff --git a/include/lib/transfer_list.h b/include/lib/transfer_list.h
index 5ea5a41..9a5e692 100644
--- a/include/lib/transfer_list.h
+++ b/include/lib/transfer_list.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Linaro Limited and Contributors. All rights reserved.
+ * Copyright (c) 2023-2024, Linaro Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -73,9 +73,8 @@
 	 */
 };
 
-struct transfer_list_entry {
-	uint16_t tag_id;
-	uint8_t reserved0; /* place holder */
+struct __attribute__((packed)) transfer_list_entry {
+	uint32_t tag_id : 24;
 	uint8_t hdr_size;
 	uint32_t data_size;
 	/*
@@ -89,6 +88,8 @@
 	 */
 };
 
+CASSERT(sizeof(struct transfer_list_entry) == U(0x8), assert_transfer_list_entry_size);
+
 void transfer_list_dump(struct transfer_list_header *tl);
 entry_point_info_t *
 transfer_list_set_handoff_args(struct transfer_list_header *tl,
@@ -113,12 +114,12 @@
 		       struct transfer_list_entry *entry);
 
 struct transfer_list_entry *transfer_list_add(struct transfer_list_header *tl,
-					      uint16_t tag_id,
+					      uint32_t tag_id,
 					      uint32_t data_size,
 					      const void *data);
 
 struct transfer_list_entry *
-transfer_list_add_with_align(struct transfer_list_header *tl, uint16_t tag_id,
+transfer_list_add_with_align(struct transfer_list_header *tl, uint32_t tag_id,
 			     uint32_t data_size, const void *data,
 			     uint8_t alignment);
 
@@ -127,7 +128,7 @@
 		   struct transfer_list_entry *last);
 
 struct transfer_list_entry *transfer_list_find(struct transfer_list_header *tl,
-					       uint16_t tag_id);
+					       uint32_t tag_id);
 
 #endif /*__ASSEMBLER__*/
 #endif /*__TRANSFER_LIST_H*/