1.Place the program on the SD card, then insert the SD card into the display.
2. When you insert the SD card, then turn off the monitor, and take off the batter or the power addapt.
3. When you achieved the step2, please attach the battery or the power adapt and then turn on the monitor.
4. select [Upgrade] on the menu.
A progress bar will appear on the screen indicating that the program is being imported.
Just wait for the flashing red and green lights to alternately indicate that it is upgrading.
When the light turns red, the upgrade is complete.
It can be used normally after restarting.
Download the V1.3.8 firmware here.
Or watch the video on my youtube channel.
Hope if helps!