Jetson Orin Nano Fails to Boot After Custom Kernel Build and Flash

Issue Overview

Users are experiencing issues with their Jetson Orin Nano development board after attempting to build a custom kernel and flash it onto the device. The specific problem is that after a seemingly successful flash process, the Jetson Orin Nano fails to boot, resulting in a dark screen. This issue occurs when users try to build and apply a real-time (RT) patched kernel using JetPack 5.1.3.

Possible Causes

1. Incorrect kernel configuration: The custom kernel build process may have resulted in a misconfigured kernel that is incompatible with the Jetson Orin Nano hardware.

2. Incomplete or corrupted flash: Although the flash process reports success, there might be issues with the actual data written to the device.

3. Missing or incompatible drivers: The custom kernel build may not include all necessary drivers for the Jetson Orin Nano, particularly display drivers.

4. PREEMPT_RT patch conflicts: The application of the real-time patch might introduce conflicts with existing Jetson-specific optimizations.

5. Bootloader issues: The flashing process may have affected the bootloader, preventing the system from initializing properly.

6. Incorrect DTB (Device Tree Blob) files: The custom build process might have generated or used incompatible DTB files for the Jetson Orin Nano.

Troubleshooting Steps, Solutions & Fixes

1. Verify flash integrity:

   • Re-run the flashing process to ensure all data is correctly written to the device.
   • Use the following command to flash:

     sudo ./tools/kernel_flash/l4t_initrd_flash.sh --external-device mmcblk1p1 \
     -c tools/kernel_flash/flash_l4t_external.xml -p "-c bootloader/t186ref/cfg/flash_t234_qspi.xml" \
     --showlogs --network usb0 jetson-orin-nano-devkit internal
     

2. Check kernel logs:

   • Set up a serial debug console to access low-level boot information.
   • Follow the guide at: https://jetsonhacks.com/2019/04/19/jetson-nano-serial-console/
   • Analyze the kernel logs for any error messages or boot failures.

3. Verify kernel configuration:

   • Review the kernel configuration file (.config) to ensure all necessary options are enabled for the Jetson Orin Nano.
   • Pay special attention to display and GPU-related configurations.

4. Rebuild without RT patch:

   • Temporarily remove the RT patch application step from the build script.
   • Rebuild and flash the kernel without RT support to isolate if the issue is related to the PREEMPT_RT patch.

5. Check display drivers:

   • Ensure the NVIDIA display drivers are correctly built and installed.
   • Verify the following files are present in the correct location:

     $ROOT/Linux_for_Tegra/rootfs/lib/modules/5.10.192-rt96-tegra/extra/opensrc-disp/nvidia-modeset.ko
     $ROOT/Linux_for_Tegra/rootfs/lib/modules/5.10.192-rt96-tegra/extra/opensrc-disp/nvidia.ko
     $ROOT/Linux_for_Tegra/rootfs/lib/modules/5.10.192-rt96-tegra/extra/opensrc-disp/nvidia-drm.ko
     

6. Update module dependencies:

   • After building and before flashing, run the following commands:

     sudo cp "${KERNEL_OUT}/System.map" ${L4T_ROOTFS_DIR}
     sudo chroot ${L4T_ROOTFS_DIR} depmod -a -F /System.map 5.10.192-rt96-tegra
     

7. Verify DTB files:

   • Ensure the correct DTB files for Jetson Orin Nano are being used.
   • Check that the DTB files are correctly copied to the kernel/dtb/ directory.

8. Use known-good configuration:

   • If possible, obtain a known-working kernel configuration for Jetson Orin Nano.
   • Use this configuration as a base and carefully apply your custom changes.

9. Check for hardware issues:

   • If possible, try booting with the original, unmodified JetPack image to rule out hardware problems.

10. Seek community support:

    • If the issue persists, gather all relevant logs and information.
    • Post a detailed description of the problem, including all troubleshooting steps taken, in the NVIDIA Developer Forums for further assistance.