/* 1. We overwrite the pin control helper node */
&uart0_default {
    group1 {
        psels = <NRF_PSEL(UART_TX, 0, 3)>,  
                <NRF_PSEL(UART_RX, 0, 11)>; 
    };
};

/* 2. Apply it to the UART peripheral */
&uart0 {
    status = "okay";
    pinctrl-0 = <&uart0_default>;
    pinctrl-names = "default";
    current-speed = <115200>; 
};