DecaRanging_5p02 - communication with PC via UART

Hey guys. I need your help with the DecaRanging app. The communication via USB works fine. However, the source code of the TWR demo also provides a variant with UART.
When starting the app the MCU receives the commands: “stop”, “uspi”, “deca?” and “reset” and executes them successfully.
Now follows the first reading via SPI (dwt_probe). I read 0xdeca0302.
In the USB case this is no problem, but in the UART case I get an error message here via the GUI.
Where is the problem and why does the DecaRanging app stop here? Is it possible to get the source code of the DecaRanging app? Gladly via NDA with the company where I work.