How to Downgrade from JetPack 6DP to JetPack 5 on Jetson Orin Nano Dev Kit (SD Card)

Issue Overview

Users attempting to downgrade their Jetson Orin Nano Developer Kit from JetPack 6DP to JetPack 5 are encountering a series of challenges. The primary symptoms include:

• Inability to select JetPack 5 in the SDK Manager, which only offers JetPack 6 DP as the selectable option.
• Flashing issues where the board becomes undetectable after attempting to flash an SD card with JetPack 5, leading to boot failures.
• Users report receiving errors during the flashing process, including "cannot open /dev/mmcblk0boot0" and "Error: Invalid argument during seek for read on /dev/mmcblk1".
• The issue is consistent across multiple users, indicating a broader compatibility or configuration problem.

The context of the problem typically arises during the setup phase when users are trying to follow tutorials that require JetPack 5. Relevant hardware specifications include using SD cards of sizes around 64GB, which some users have found insufficient for JetPack 5 due to sector size requirements.

Possible Causes

1. Hardware Incompatibilities:

   • Users have reported using SD cards that are slightly smaller than required (e.g., 57-58 GB), which may lead to issues during flashing and booting.

2. Software Bugs or Conflicts:

   • The SDK Manager may not properly support downgrading from JetPack 6DP to JetPack 5, especially on newer Ubuntu versions like 22.04.

3. Configuration Errors:

   • Incorrect setup of the SDK Manager or failure to properly enter recovery mode can prevent successful flashing.

4. Driver Issues:

   • Outdated or incompatible drivers may hinder the detection of the board during flashing attempts.

5. Environmental Factors:

   • Power supply issues or overheating could affect the board’s ability to flash correctly.

6. User Errors:

   • Misconfigurations in the flashing process, such as not formatting the SD card correctly or not following recovery mode procedures.

Troubleshooting Steps, Solutions & Fixes

1. Preparation Steps:

   • Ensure that you are using a compatible version of Ubuntu (preferably Ubuntu 20.04) before attempting to downgrade.
   • Use a minimum of a 64GB SD card, preferably larger, and ensure it is formatted correctly (FAT32 recommended).

2. Flashing Process:

   • Download the necessary JetPack 5 image from NVIDIA’s official site.
   • Use a reliable tool (like Balena Etcher) to flash the image onto your SD card.
   • Ensure that the SD card is cleanly formatted before flashing.

3. Entering Recovery Mode:

   • To enter recovery mode, short pins 9 and 10 on the board while powering it on. This will allow your host PC to detect the device.

4. Using SDK Manager:

   • Launch SDK Manager while your board is in recovery mode.
   • Select "Jetson Orin Nano Developer Kit" as your target hardware and ensure only "Jetson OS" is selected for installation.
   • If you encounter issues with detection, try different USB ports or cables.

5. Manual Flashing:

   • If SDK Manager fails, consider using command-line tools for manual flashing:

     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
     

   • Adjust sector sizes by specifying EXT_NUM_SECTORS if your SD card is smaller than required.

6. Post-Flashing Issues:

   • If you successfully flash but cannot boot, check if the bootloader needs downgrading as well.
   • Refer to logs generated during flashing for specific errors that can guide further troubleshooting.

7. Best Practices:

   • Always keep your firmware updated before attempting significant changes.
   • Regularly back up your configurations and important data before flashing new images.
   • Consult NVIDIA’s documentation for any updates on compatibility and troubleshooting specific error messages encountered during setup.

By following these steps and utilizing community insights from users who have successfully downgraded, you can increase your chances of resolving issues related to downgrading from JetPack 6DP to JetPack 5 on the Jetson Orin Nano Dev Kit.