diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 4dbb10aff3..444f41cf8c 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -1102,6 +1102,7 @@ static void stream_blob(uintmax_t len, struct object_id *oidout, uintmax_t mark)
 		|| (pack_size + PACK_SIZE_THRESHOLD + len) < pack_size)
 		cycle_packfile();
 
+	the_hash_algo->init_fn(&checkpoint.ctx);
 	hashfile_checkpoint(pack_file, &checkpoint);
 	offset = checkpoint.offset;
 
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 006ffdc9c5..dda94a9f46 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -1166,6 +1166,7 @@ static void parse_pack_objects(unsigned char *hash)
 	struct ofs_delta_entry *ofs_delta = ofs_deltas;
 	struct object_id ref_delta_oid;
 	struct stat st;
+	git_hash_ctx tmp_ctx;
 
 	if (verbose)
 		progress = start_progress(
@@ -1202,7 +1203,9 @@ static void parse_pack_objects(unsigned char *hash)
 
 	/* Check pack integrity */
 	flush();
-	the_hash_algo->final_fn(hash, &input_ctx);
+	the_hash_algo->init_fn(&tmp_ctx);
+	the_hash_algo->clone_fn(&tmp_ctx, &input_ctx);
+	the_hash_algo->final_fn(hash, &tmp_ctx);
 	if (!hasheq(fill(the_hash_algo->rawsz), hash))
 		die(_("pack is corrupted (SHA1 mismatch)"));
 	use(the_hash_algo->rawsz);
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 32505255a0..fef7423448 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -609,6 +609,7 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix UNUSED)
 {
 	int i;
 	struct object_id oid;
+	git_hash_ctx tmp_ctx;
 
 	disable_replace_refs();
 
@@ -669,7 +670,9 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix UNUSED)
 	the_hash_algo->init_fn(&ctx);
 	unpack_all();
 	the_hash_algo->update_fn(&ctx, buffer, offset);
-	the_hash_algo->final_oid_fn(&oid, &ctx);
+	the_hash_algo->init_fn(&tmp_ctx);
+	the_hash_algo->clone_fn(&tmp_ctx, &ctx);
+	the_hash_algo->final_oid_fn(&oid, &tmp_ctx);
 	if (strict) {
 		write_rest();
 		if (fsck_finish(&fsck_options))
diff --git a/bulk-checkin.c b/bulk-checkin.c
index 73bff3a23d..92b9c8598b 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -268,6 +268,7 @@ static int deflate_to_pack(struct bulk_checkin_packfile *state,
 					  type, size);
 	the_hash_algo->init_fn(&ctx);
 	the_hash_algo->update_fn(&ctx, obuf, header_len);
+	the_hash_algo->init_fn(&checkpoint.ctx);
 
 	/* Note: idx is non-NULL when we are writing */
 	if ((flags & HASH_WRITE_OBJECT) != 0)
diff --git a/csum-file.c b/csum-file.c
index cd01713244..870748e016 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -207,7 +207,7 @@ int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint
 	    lseek(f->fd, offset, SEEK_SET) != offset)
 		return -1;
 	f->total = offset;
-	f->ctx = checkpoint->ctx;
+	the_hash_algo->clone_fn(&f->ctx, &checkpoint->ctx);
 	f->offset = 0; /* hashflush() was called in checkpoint */
 	return 0;
 }