L4T Launcher Unable to Find Extlinux on Nvidia Jetson Orin Nano Dev Board

Issue Overview

Users of the Nvidia Jetson Orin Nano Dev board are experiencing an issue where the L4T Launcher is unable to find extlinux when booting from an SD card. The specific error message displayed in the UART console is:

"L4TLauncher: Unable to boot via extlinux: Not Found"

This issue occurs during the boot process, particularly when using a cloned image or when copying the contents of the original image’s rootfs to a custom system.img. Despite this error, the boot process continues successfully by switching to kernel boot. The problem does not appear when using the original, properly flashed image.

Possible Causes

1. Cloning Process Issues: The use of dd to clone the image may not properly replicate all necessary boot components.

2. Bootloader Configuration: The UEFI bootloader can see the extlinux.conf file but is unable to use extlinux to boot the OS, suggesting a possible configuration issue.

3. Partition Layout Changes: Modifications to the partition layout, especially when attempting to use an encrypted rootfs, may affect the bootloader’s ability to locate extlinux.

4. Firmware or Driver Incompatibilities: There could be inconsistencies between the cloned image and the hardware-specific firmware or drivers.

5. SD Card Compatibility: The issue might be related to how the SD card interacts with the cloned or custom image.

Troubleshooting Steps, Solutions & Fixes

1. Verify Original Image Integrity:

   • Ensure the original image boots normally without the extlinux error.
   • Compare the partition layout and boot files between the original and cloned images.

2. Use NVIDIA SDK Manager:

   • Instead of using dd or manual copying, try flashing the image using the NVIDIA SDK Manager.
   • This tool is designed to properly set up Jetson devices and may resolve bootloader-related issues.

3. Check extlinux.conf Location:

   • Verify that the extlinux.conf file is in the correct location.
   • If moved, the L4T Launcher displays a different message indicating the file was not found.

4. Examine Boot Partition:

   • Ensure that the /boot partition contains the necessary kernel, initrd, and DTB files.
   • Compare these files with the original image to identify any discrepancies.

5. Review Flashing Process:

   • If using the flash.sh script, review the flashing process log for any errors or warnings.
   • Consider posting the flashing process log for further analysis.

6. Custom Boot Configuration:

   • For advanced setups (e.g., encrypted rootfs), research Jetson-specific boot methods.
   • Consult NVIDIA documentation for supported boot configurations on the Orin Nano devkit.

7. Update L4T and Firmware:

   • Ensure you’re using the latest L4T (Linux for Tegra) version compatible with your device.
   • Check for any available firmware updates for the Orin Nano devkit.

8. Kernel Boot Parameters:

   • Examine and modify kernel boot parameters if necessary.
   • This can be done by editing the extlinux.conf file or through the UEFI interface if available.

9. SD Card Troubleshooting:

   • Try using a different SD card to rule out card-specific issues.
   • Ensure the SD card is properly formatted and compatible with the Jetson device.

10. Community Support:

    • If the issue persists, consider opening a new support thread on the NVIDIA Developer Forums.
    • Provide detailed information about your setup, including L4T version, flashing method, and full boot logs.

Remember that while the current workaround (falling back to kernel boot) allows the system to boot, resolving the extlinux issue is important for maintaining proper boot processes and enabling advanced configurations like encrypted rootfs partitions.