Change in the folder kernel/arch/arm/boot/dts/overlays: sun8i_h3_uart1.dts "pinctrl-0 = <&uart1_pins>;" to "pinctrl-0 = <&uart1_pins>,<&uart1_rts_cts_pins>;" sun8i_h3_nanopi.dtsi "pinctrl-0 = <&uart1_pins>;" to "pinctrl-0 = <&uart1_pins>, <&...