Why the /dev/ttyTHS2 can not receive data at TX1 jetpack 3.1,but jetpack 3.0 is OK?

Why the /dev/ttyTHS2 can not receive data at TX1 jetpack 3.1,but jetpack 3.0 is OK?

I’ve used it with R27.1 through R28.2, which works. However, I’ve only used it at speed 115200 or slower. Can you give details on all settings (including if flow control is used) and what is connected? Is there any significant cable length, and is the cable of good quality (e.g., twisted pair)? Can you try loopback where you both send and receive on ttyTHS2, but J17 TX and RX are jumpered (don’t use CTS/RTS flow control)?