To get a fully functional images one has to put debian image in the packages directory:
- linux image package
- linux header package
- u-boot package
- rockchip-firmware
Those can be build using scripts available at https://github.com/Joshua-Riek/ubuntu-rockchip or its ppa.
sudo USER=user SSH_PUB_KEY_FILE=/home/user/.ssh/id_rsa.pub sh script.sh
To move data to nvme, there's a script /usr/bin/nvme-install.sh