Programming rak5010 on segger embedded studio

Hi everybody!
I am trying to program rak5010 on segger embedded studio. Now, I have successfully programmed I2C to communicate with sensors on rak5010. But when I do UART communication with bg96, I got error NRF_BREAKPOINT_COND; I have researched and found a solution is to use a resistor to pull the RX pin to VCC. But the firmware of rak5010 still works fine without modifying the circuit.
Has anyone succeeded in programming rak5010 using segger embedded studio?
I would need a little help