diff --git a/cache-tree.c b/cache-tree.c
index 641427ed41..ddc7d3d869 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -448,7 +448,7 @@ static int update_one(struct cache_tree *it,
 		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 				 OBJ_TREE, &it->oid);
 	} else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
-					   &it->oid, flags & WRITE_TREE_SILENT
+					   &it->oid, NULL, flags & WRITE_TREE_SILENT
 					   ? HASH_SILENT : 0)) {
 		strbuf_release(&buffer);
 		return -1;
diff --git a/object-file.c b/object-file.c
index 4e55f475b3..820810a5f4 100644
--- a/object-file.c
+++ b/object-file.c
@@ -2235,7 +2235,7 @@ int stream_loose_object(struct input_stream *in_stream, size_t len,
 
 int write_object_file_flags(const void *buf, unsigned long len,
 			    enum object_type type, struct object_id *oid,
-			    unsigned flags)
+			    struct object_id *compat_oid_in, unsigned flags)
 {
 	struct repository *repo = the_repository;
 	const struct git_hash_algo *algo = repo->hash_algo;
@@ -2246,7 +2246,9 @@ int write_object_file_flags(const void *buf, unsigned long len,
 
 	/* Generate compat_oid */
 	if (compat) {
-		if (type == OBJ_BLOB)
+		if (compat_oid_in)
+			oidcpy(&compat_oid, compat_oid_in);
+		else if (type == OBJ_BLOB)
 			hash_object_file(compat, buf, len, type, &compat_oid);
 		else {
 			struct strbuf converted = STRBUF_INIT;
diff --git a/object-store-ll.h b/object-store-ll.h
index bc76d6bec8..c5f2bb2fc2 100644
--- a/object-store-ll.h
+++ b/object-store-ll.h
@@ -255,11 +255,11 @@ void hash_object_file(const struct git_hash_algo *algo, const void *buf,
 
 int write_object_file_flags(const void *buf, unsigned long len,
 			    enum object_type type, struct object_id *oid,
-			    unsigned flags);
+			    struct object_id *comapt_oid_in, unsigned flags);
 static inline int write_object_file(const void *buf, unsigned long len,
 				    enum object_type type, struct object_id *oid)
 {
-	return write_object_file_flags(buf, len, type, oid, 0);
+	return write_object_file_flags(buf, len, type, oid, NULL, 0);
 }
 
 int write_object_file_literally(const void *buf, unsigned long len,