diff --git a/archive-tar.c b/archive-tar.c
index fd622eacc0..7a0d31d847 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -119,7 +119,7 @@ static int stream_blocked(const struct object_id *oid)
 	char buf[BLOCKSIZE];
 	ssize_t readlen;
 
-	st = open_istream(oid->hash, &type, &sz, NULL);
+	st = open_istream(oid, &type, &sz, NULL);
 	if (!st)
 		return error("cannot stream blob %s", oid_to_hex(oid));
 	for (;;) {
diff --git a/archive-zip.c b/archive-zip.c
index 5841a6ceb6..18b951b732 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -337,7 +337,7 @@ static int write_zip_entry(struct archiver_args *args,
 
 		if (S_ISREG(mode) && type == OBJ_BLOB && !args->convert &&
 		    size > big_file_threshold) {
-			stream = open_istream(oid->hash, &type, &size, NULL);
+			stream = open_istream(oid, &type, &size, NULL);
 			if (!stream)
 				return error("cannot stream blob %s",
 					     oid_to_hex(oid));
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index b28ebfadd4..ae11d2a610 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -771,7 +771,7 @@ static int check_collison(struct object_entry *entry)
 
 	memset(&data, 0, sizeof(data));
 	data.entry = entry;
-	data.st = open_istream(entry->idx.oid.hash, &type, &size, NULL);
+	data.st = open_istream(&entry->idx.oid, &type, &size, NULL);
 	if (!data.st)
 		return -1;
 	if (size != entry->size || type != entry->type)
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index a197926eaa..8307cc9b04 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -267,7 +267,7 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
 	if (!usable_delta) {
 		if (entry->type == OBJ_BLOB &&
 		    entry->size > big_file_threshold &&
-		    (st = open_istream(entry->idx.oid.hash, &type, &size, NULL)) != NULL)
+		    (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 			buf = NULL;
 		else {
 			buf = read_sha1_file(entry->idx.oid.hash, &type,
diff --git a/sha1_file.c b/sha1_file.c
index e4cb840661..cdcba4483b 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -799,7 +799,7 @@ int check_object_signature(const struct object_id *oid, void *map,
 		return oidcmp(oid, &real_oid) ? -1 : 0;
 	}
 
-	st = open_istream(oid->hash, &obj_type, &size, NULL);
+	st = open_istream(oid, &obj_type, &size, NULL);
 	if (!st)
 		return -1;
 
diff --git a/streaming.c b/streaming.c
index 5892b50bd8..be85507922 100644
--- a/streaming.c
+++ b/streaming.c
@@ -130,14 +130,14 @@ static enum input_source istream_source(const unsigned char *sha1,
 	}
 }
 
-struct git_istream *open_istream(const unsigned char *sha1,
+struct git_istream *open_istream(const struct object_id *oid,
 				 enum object_type *type,
 				 unsigned long *size,
 				 struct stream_filter *filter)
 {
 	struct git_istream *st;
 	struct object_info oi = OBJECT_INFO_INIT;
-	const unsigned char *real = lookup_replace_object(sha1);
+	const unsigned char *real = lookup_replace_object(oid->hash);
 	enum input_source src = istream_source(real, type, &oi);
 
 	if (src < 0)
@@ -507,7 +507,7 @@ int stream_blob_to_fd(int fd, const struct object_id *oid, struct stream_filter
 	ssize_t kept = 0;
 	int result = -1;
 
-	st = open_istream(oid->hash, &type, &sz, filter);
+	st = open_istream(oid, &type, &sz, filter);
 	if (!st) {
 		if (filter)
 			free_stream_filter(filter);
diff --git a/streaming.h b/streaming.h
index 73c1d156b3..32f4626771 100644
--- a/streaming.h
+++ b/streaming.h
@@ -8,7 +8,7 @@
 /* opaque */
 struct git_istream;
 
-extern struct git_istream *open_istream(const unsigned char *, enum object_type *, unsigned long *, struct stream_filter *);
+extern struct git_istream *open_istream(const struct object_id *, enum object_type *, unsigned long *, struct stream_filter *);
 extern int close_istream(struct git_istream *);
 extern ssize_t read_istream(struct git_istream *, void *, size_t);