You need to modify the Devicetree.
/opt/source/dtb-5.10-ti/
or
I modified ‘k3-j721e-beagleboneai64-bone-buses.dtsi’ and ‘k3-j721e-beagleboneai64.dts’
Below is an example.
bone_uart_3: &main_uart3 {
/* tested /
pinctrl-names = “default”;
pinctrl-0 = <
&P9_17_uart_pin / uart3_txd /
&P9_12_uart_pin / uart3_rxd */
;
symlink = “bone/uart/3”;
status = “okay”;
};
A similar correction would do.
I referred to the pin map [Connectors — BeagleBoard Documentation ]