If you are having a NanoPi R6C variant, replace fdtfile=rockchip/rk3588s-nanopi-r6s.dtb
in /boot/armbianEnv.txt with fdtfile=rockchip/rk3588s-nanopi-r6c.dtb

If you are having a NanoPi R6C variant, replace fdtfile=rockchip/rk3588s-nanopi-r6s.dtb
in /boot/armbianEnv.txt with fdtfile=rockchip/rk3588s-nanopi-r6c.dtb
sudo armbian-install
). Make sure to generate partitions and format them before start.