diff --git a/src/commonlib/device_tree.c b/src/commonlib/device_tree.c
index cb7a596bc5..b2daac9cd8 100644
--- a/src/commonlib/device_tree.c
+++ b/src/commonlib/device_tree.c
@@ -935,12 +935,11 @@ void dt_flatten(const struct device_tree *tree, void *start_dest)
 
 	uint8_t *struct_start = dest;
 	header->structure_offset = htobe32(dest - (uint8_t *)start_dest);
+	be32enc(&dest[struct_size], FDT_TOKEN_END);
+	struct_size += sizeof(uint32_t);
 	header->structure_size = htobe32(struct_size);
 	dest += struct_size;
 
-	*((uint32_t *)dest) = htobe32(FDT_TOKEN_END);
-	dest += sizeof(uint32_t);
-
 	uint8_t *strings_start = dest;
 	header->strings_offset = htobe32(dest - (uint8_t *)start_dest);
 	header->strings_size = htobe32(strings_size);