JetPack7.1 short the UART1_RX/UART1_TX pin stay at uefi

Robotics & Edge Computing Jetson Systems Jetson Thor
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  1. short the UART1_RX/UART1_TX pin , power on, stay at uefi
  2. do not short the UART1_RX/UART1_TX pin, power on, enter system normal
  3. UART1 is UJ3 (uart9: serial@810c530000)
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jetson_thor_log.txt (44.4 KB)

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Hi feiniao08102,

Are you using the devkit or custom board for Thor?
What’s the Jetpack version in use?

From the log you shared, it seems booting into UEFI menu.
Please try to keep it booting through Boot Manager → Your boot device .

Could you also share the result of the following command on your board?

$ cat /proc/cmdline
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  1. custom board

  2. short the uart1_rx and uart1_tx, booting into UEFI menu

    image
    image808×383 10.4 KB

  3. jetpack7.1

cat /etc/nv_tegra_release 
# R38 (release), REVISION: 4.0, GCID: 43443517, BOARD: generic, EABI: aarch64, DATE: Wed Dec 31 00:15:19 UTC 2025
# KERNEL_VARIANT: oot
TARGET_USERSPACE_LIB_DIR=nvidia
TARGET_USERSPACE_LIB_DIR_PATH=usr/lib/aarch64-linux-gnu/nvidia
INSTALL_TYPE=openrm

nvidia@tegra-ubuntu:~$ cat /proc/cmdline 
root=PARTUUID=4151317c-a96a-4d52-9711-2b784bd41449 rw rootwait rootfstype=ext4 mminit_loglevel=4 earlycon=tegra_utc,mmio32,0xc5a0000 console=ttyUTC0,115200 clk_ignore_unused firmware_class.path=/etc/firmware fbcon=map:0 efi=runtime audit_backlog_limit=8192 video=efifb:off console=tty0 bl_prof_dataptr=6225920@0x2004010000 bl_prof_ro_ptr=65536@0x2004000000
  1. if do not short the uart1_rx and uart1_tx, booting into system normal(Ubuntu 24.04.3 LTS)
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Do you have the requirement to enter into UEFI menu?
If not, please refer to the following thread to disable this function.
Close or hide UEFI menu - #3 by KevinFFF

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need to enter into UEFI menu

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Could you try keeping UEFI and kernel DTB separate?

By default, kernel and UEFI use the similar DTB as following(snippet from jetson-agx-thor-devkit.conf )

DTB_FILE="tegra264-p4071-0000+p3834-0008-nv.dtb";
TBCDTB_FILE="${DTB_FILE}";

i.e. please disable the UART interfaces from UEFI DTB(TBCDTB_FILE) and enable them in kernel DTB(DTB_FILE).

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  1. disable the UART interfaces from UEFI DTB(TBCDTB_FILE ) and enable them in kernel DTB(DTB_FILE ).
  2. reflash qspi, kernel dtb use TBCDTB_FILE not DTB_FILE.
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Please specify FDT in extlinux.conf so kernel should use the DTB from there.