Query on Kernel Configuration Not Persisting During Build

Robotics & Edge Computing Jetson Systems Jetson Orin NX
1

Hi @JerryChang
We are facing an issue while modifying and building the kernel configuration in our current setup.

We attempted to update the kernel configuration using make menuconfig and then build the kernel using make -C kernel. However, after saving the changes and triggering the build, the modified configuration does not persist. During the build process, we observe the following message:

“Default configuration is based on ‘defconfig’”
“arch/arm64/configs/defconfig:1357: warning: override: reassigning to symbol BRCMFMAC_SDIO”
“No change to .config”

It appears that the build system is reloading the default defconfig, thereby overwriting the changes made via menuconfig.

Could you please confirm the correct procedure to modify and rebuild the kernel configuration in this environment? Specifically, we would like to understand how to ensure that our configuration changes are retained and reflected in the final build.

Thanks & Regards

4

hello rahul.pp,

please refer to developer guide, Kernel Customization to rebuild the kernel manually.

6

Hi @JerryChang
Thank you for your reply.
We have also followed the steps mentioned in the Developer Guide under Kernel Customization for rebuilding the kernel manually.

    1. cd /Linux_for_Tegra/source
    2. export CROSS_COMPILE=/bin/aarch64-buildroot-linux-gnu-
    3. make -C kernel
    4. export INSTALL_MOD_PATH=/Linux_for_Tegra/rootfs/
    5. sudo -E make install -C kernel
      cp kernel/kernel-jammy-src/arch/arm64/boot/Image
      /Linux_for_Tegra/kernel/Image

However, even after modifying the kernel configuration and saving the changes, the build process still reloads the default defconfig, and the updated configuration is not reflected in the final build.

Could you please help confirm if any additional steps are required to preserve the modified kernel configuration during the build process?

7

hello ahul.pp,

please refer to below from developer guide, Process Overview to Bring Your Own Kernel.

To update a config, run the ./scripts/config --file "arch/arm64/configs/defconfig" --enable <config> command in the kernel directory.