There are 4 steps to update kernel config.
Step 1. Generate base kernel config (.config)
$ cd <Linux_for_Tegra>/sources/kernel/kernel-5.10
$ make ARCH=arm64 defconfig
Step 2. Configure the kernel config in menu and update .config
$ make ARCH=arm64 menuconfig
Step 3. Generate defconfig
$ make ARCH=arm64 savedefconfig
Step 4. Update defconfig
$ cp defconfig arch/arm64/configs/defconfig
You can also add the specific kernel config in arch/arm64/configs/defconfig directly.
After boot up, please run the following command to check if it is applied correctly.
$ zcat /proc/config.gz | grep CONFIG_VIDEO_IMX412