Hi Jill lu,
You don't need to return 30.xx version, I know how to solve this problem from your picture now!
Your picture shows the com of your twr-k40x256 is COM10, but your P&E terminal window just support COM1-COM8, COM10 is larger than COM8, so the terminal window can't find it, COM10 is out of range.
Now please modify your your twr-k40x256 com number by this way:
1. double click OSBDM/OSJTAG-CDC serial Port...(COM10) in your picture, you will get the property of this COM port interface.
2. Select"Port Settings",
3, Select"Advanced.."
4, modify the COM Port number to below COM8, and click all the OK button.
5, power off and power on again, you will find your board's port is the COM number which you defined.

After you modify it successfully, please select the according COM port in your P&E terminal window.
Wish it helps you!
If you still have question, please contact with me!
Have a great day,
Jingjing
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