This upgrade file applies for the ZR16LK/00 DVR. 

You can find your DVR's model number on the label at the bottom of your DVR.

Please follow up the below video to upgrade the DVR:

https://www.youtube.com/watch?v=bUlFCp4xlu0

The below is the detail steps to upgrade the DVR:

(1). You needn't open the upgrade file, please directly download the upgrade file

     and save it to your U-disk.  

    (Please save the upgrade file rootfs-3531a in the root directory, not save it under any other

    folders.)

    Note:  it is better to use a 16GB or smaller flash drive with a Fat32 format. 

(2). The file's name should be rootfs-3531a, can not be have any changes, 

      if the file's name change to rootfs-3531a(1), the upgrade will be failed.

(3). Before starting to upgrade, please remove the mouse and unplug the power supply,

      then plug the U-disk into the DVR's USB port, and plug the power supply. 

(4).  It can upgrade automatically as long as it has electricity, the upgrade process need

       to last several minutes, please be patient. 

After upgraded, Please go to the DVR’s main menu – information – System to check the version.

If the upgrade was failed, we suggest you change another U-disk or USB port to try.

Please don't worry, if this can't help you, please feel free to contact us.