How to change U-BOOT debug UART port to UARTC on TX2 NX?

I have already tried to do below changes, but still cannot see the debug log:

Linux_for_Tegra/bootloader/t186ref/BCT/tegra186-mb1-bct-misc-si-l4t.cfg:

debug variables

debug.enable_log = 1;
-debug.uart_instance = 0;
+debug.uart_instance = 2;

u-boot/include/configs/p3636-0001.h:
+#define CONFIG_TEGRA_ENABLE_UARTC

cboot debug log can output well from UARTC, and if I add console=ttyS2,115200n8 into CMDLINE_ADD, there also a few kernel log output from the UARTC. But I can’t see any U-BOOT debug log.
TX2_NX_BOOTUP_LOG.log (19.7 KB)

Hi ifish85,

Are you using the devkit or custom board for TX2-NX?
What’s your Jetpack version in use?

Is there any purpose that you don’t want to use default debug UART to output log?

Hi KevinFFF,

  1. I am using custom board for TX2-NX.
  2. The Jetpack version is 4.6.4
  3. The default debug UART is used for communicate with another MCU

May I know why you don’t use UARTC to communicate with MCU and keep debug UART output the debug messages?

Please share the full dmesg for further check.

Hi KevinFFF,
From our HW team, it is just be chosen freely when designing, no special reason.
So the UARTC cannot used for output U-BOOT debug log? but why cboot and kernel debug log can output well?
Another question, can we just remove the U-BOOT by setting USE_UBOOT=0 in p3636.conf.common? will it bring any other affect?

dmesg.log (60.2 KB)

You could re-direct the UART messages to another interface as the following thread(for Orin NX) but we don’t verify this use case and not suggest doing that. You may also need to configure the register for bpmp.
Orin NX Uart Problem - #7 by KevinFFF

The default combined UART output many debug messages from different stage (MB1/MB2/bootloader/kernel) and you would need to disable it from different configuration files. It is not the suggested use case.

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