Here is my procedure(following NVIDIA DOCS):
cd /home/kwt/l4t-gcc
tar xf gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu.tar.xz
cd
tar -xjf public_sources.tbz2
cd Linux_for_Tegra/source/public
tar -xjf kernel_src.tbz2
patch --verbose -p1 < l4t-32.6.1-nx.patch
sudo apt install -y build-essential bc
TEGRA_KERNEL_OUT=/home/kwt/tegra-kernel-out
export CROSS_COMPILE=/home/kwt/l4t-gcc/gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-
export LOCALVERSION=-tegra
cd kernel/kernel-4.9
mkdir -p $TEGRA_KERNEL_OUT
make ARCH=arm64 O=$TEGRA_KERNEL_OUT tegra_defconfig
make ARCH=arm64 O=$TEGRA_KERNEL_OUT -j16
cd /home/kwt/flash
sudo tar xf Jetson_Linux_R32.6.1_aarch64.tbz2
cd Linux_for_Tegra/rootfs/
sudo tar xpf ../../Tegra_Linux_Sample-Root-Filesystem_R32.6.1_aarch64.tbz2
cd ..
sudo cp $TEGRA_KERNEL_OUT/arch/arm64/boot/Image ./kernel/Image
sudo cp $TEGRA_KERNEL_OUT/arch/arm64/boot/dts/* ./kernel/dtb/
cd /home/kwt/Linux_for_Tegra/source/public/kernel/kernel-4.9
sudo make ARCH=arm64 O=$TEGRA_KERNEL_OUT modules_install INSTALL_MOD_PATH=/home/kwt/flash/Linux_for_Tegra/rootfs/
cd /home/kwt/flash/Linux_for_Tegra
sudo ./apply_binaries.sh
sudo ./flash.sh jetson-xavier-nx-devkit-emmc mmcblk0p1
All steps seem to work, but there is no /dev/video0
Maybe I made a wrong use of the patch file?