RS485 Not Working After Upgrading to Jetpack 36.4 on Jetson AGX Orin with jetpack 6.1

Thanks for sharing the info.
I’ve checked your dmesg and device tree.
It seems /dev/ttyTHS3(serial@3140000) use different mode in serial.

Please remove the following lines in device tree of R36.4.0 to check if it could help in your case.

		serial@3140000 {
			clock-names = "serial";
			resets = <0x03 0x68>;
			interrupts = <0x00 0x74 0x04>;
			clocks = <0x03 0x9f>;
-			dma-names = "rx\0tx";
			compatible = "nvidia,tegra194-hsuart";
			status = "okay";
			reg = <0x00 0x3140000 0x00 0x10000>;
			phandle = <0x229>;
-			dmas = <0xee 0x14 0xee 0x14>;
			reset-names = "serial";
		};