Disabling combined UART in JetPack 5.1.1 on Xavier NX

Robotics & Edge Computing Jetson Systems Jetson Xavier NX
,
13

I made the changes below to the three files only. The net result was that the Xavier NX does boot successfully but the UART is clearly still being used as a debug UART during boot. I have attached the log from the debug UART
debug_port.log (12.1 KB). Also note that /dev/ttyTCU0 still exists so the combined UART is still being created.

JetPack 5.1.1 Device Tree Changes

p3668.conf.common

Changed:

	TBCDTB_FILE=tegra194-p3668-all-p3509-0000.dtb;
	CMDLINE_ADD="console=ttyTCU0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0";
	target_board="t186ref";

to:

	TBCDTB_FILE=tegra194-p3668-all-p3509-0000.dtb;
	CMDLINE_ADD="console=tty0 fbcon=map:0 net.ifnames=0";
	target_board="t186ref";

tegra194-a02-bpmp-p3668-a00.dtb

Removed:

		serial {
				port = <0x3>;
				has_input;
				
				combined-uart {
					enabled;
				}
		};

tegra194-p3668-all-p3509-0000.dtb

Changed:

	combined-uart {
		compatible = "nvidia,tegra194-tcu\0nvidia,tegra186-combined-uart";
		reg = <0x00 0x3c10000 0x00 0x04 0x00 0xc168000 0x00 0x04 0x00 0x3c00000 0x00 0x1000>;
		interrupts = <0x00 0x78 0x04>;
		mboxes = <0x1c 0x01 0x00 0x1d 0x01 0x80000001>;
		mbox-names = "rx\0tx";
		skip-frame-info;
		status = "okay";
		console-port;
		combined-uart;
	};

to:

	combined-uart {
		compatible = "nvidia,tegra194-tcu\0nvidia,tegra186-combined-uart";
		reg = <0x00 0x3c10000 0x00 0x04 0x00 0xc168000 0x00 0x04 0x00 0x3c00000 0x00 0x1000>;
		interrupts = <0x00 0x78 0x04>;
		mboxes = <0x1c 0x01 0x00 0x1d 0x01 0x80000001>;
		mbox-names = "rx\0tx";
		skip-frame-info;
		status = "disabled"; /* DRM: was "okay" */
		console-port;
		combined-uart;
	};