Armbian updates the kernel packages on their repository very rarely, while the build system is several patch versions ahead. There is a newer build available on our server:
wget https://dietpi.com/downloads/binaries/linux-{image,dtb}-current-rockchip64.deb
dpkg -i linux-{image,dtb}-current-rockchip64.deb
rm linux-{image,dtb}-current-rockchip64.deb
I have not tested this on my ROCK Pi S in particular, so have a backup prepared, at best of the whole SD card.