I’m running without X11
sudo systemctl enable multi-user.target
sudo systemctl set-default multi-user.target
and I did build kernel on the target which is terribly slow
apply rt patches
cd kernel-4.9/scripts
./rt-patch.sh apply-patches
make menuconfig
enable rt_full preemption
make -j4 Image
make -j4 modules
backup old kernel
sudo cp /boot/Image /boot/Image.original
sudo make modules_install
sudo cp arch/arm64/boot/Image /boot/Image
sudo make headers_install INSTALL_HDR_PATH=/usr