BX3105 UART headers not working

I am trying to get the UART headers on the BX3105 working - transferring AT commands to configure and send data via the WiFi module. It is not working - I switched the jumper to UART setting and attached the TX/RX and ground pins on the header. I also tried various means powering the device, including USB, the 3V3 test point and the VUSB 5V test point but no joy.

USB mode works perfectly though. I notice that there is another similar post with no replies - sorry if it is a silly question but a hint or two in the right direction will be greatly appreciated.

I am using a USB2UART bridge to connect with the module at the moment. I tried to ping of the system (AT cmd ‘ATI\r’) and is able to get the correct ACK in USB mode but not in UART mode.


I have confirmed that the problem lies on the host MCU side, thanks anyway.