Orange Pi 2G-IOT UART issue

bobby501

Hi all,
i have connected a simple GPS receiver to my Orange Pi 2G-IOT with Android 4.4, which sends data every second terminated by a carriage return.
the receiver is connected to my Orange Pi via UART(ttyS2).

At the beginning, the communication works fine and I am able to send data with "echo 'test' > /dev/ttyS2" command and receive data with "cat /dev/ttyS2" command.
But after some random time (30 mins - 5h), no more data is transferred via ttyS2.

I have tried to restart the device or reset the UART, when no more data is received (after a certain amount of time),
but this is not working. Only when I power it off/on, it is working again properly.

Does anybody have any idea how to solve this problem?
Best regards.