Update openclaw_hf/backup.py

openclaw_hf/backup.py

@@ -2443,8 +2443,8 @@ class OpenClawBackup:
                 print("restore skipped: a backup or restore is already in progress")
                 return False
 
-            lock_fd.write(f"{os.getpid()}\n{utc_now().isoformat()}\nrestore\n")
-            lock_fd.flush()
+            os.write(lock_fd, f"{os.getpid()}\n{utc_now().isoformat()}\nrestore\n".encode())
+            os.fsync(lock_fd)
 
             result = self._restore_inner()
         except TimeoutError as e: