Hi
@Thanh Nguyen
Answers to your questions are below:
1) Have you set your record schedule for the cameras to record by event? You need to go to
Configuration > Storage > Schedule Settings > Record Schedule and set the schedule to be event (usually the purple colour).
2) I don't understand what you mean by "I couldn't set camera 2 as it always comes back to preset of camera 1", can you please explain what you are trying to do in more detail?
3) The K-series NVRs still do not offer full browser support for modern browsers like Chrome, Firefox, etc... and so we would still recommend that you access the 7604(B) NVR with Internet Explorer or Hikvision's free VMS -
iVMS-4200
Both your cameras and NVR are already running the latest firmware, both firmware versions are already newer than the vulnerable firmware so there is no need to update.