Before everything you must install and download something for ready.
We are using Ubuntu 18
Install some software
apt-get install repo git u-boot-tools device-tree-compiler mtools parted libudev-dev libusb-1.0-0-dev python-linaro-image-tools linaro-image-tools gcc-arm-linux-gnueabihf gcc-aarch64-linux-gnu autoconf autotools-dev libsigsegv2 m4 intltool libdrm-dev curl sed make binutils build-essential gcc g++ bash patch gzip bzip2 perl tar cpio python unzip rsync file bc wget libncurses5 libqt4-dev libglib2.0-dev libgtk2.0-dev libglade2-dev cvs mercurial rsync openssh-client subversion asciidoc w3m dblatex graphviz python-matplotlib libssl-dev pv e2fsprogs fakeroot devscripts libi2c-dev libncurses5-dev texinfo liblz4-tool genext2fs libc6-i386 lib32stdc++6 netpbm
git clone https://github.com/yeacreate-opensources/rockchip-mkbootimg.git
apt-get install libssl-dev
cd rockchip-mkbootimg/
make
make install
Download some repos
cd /home;mkdir ntablet;cd ntablet
git clone https://github.com/yeacreate-opensources/tools.git
git clone https://github.com/yeacreate-opensources/rkbin.git
git clone https://github.com/yeacreate-opensources/kernel.git
git clone https://github.com/yeacreate-opensources/rkbin.git
git clone https://github.com/yeacreate-opensources/prebuilts.git
git clone https://github.com/yeacreate-opensources/rkdocs.git
git clone https://github.com/yeacreate-opensources/ntablet_documents.git
git clone https://github.com/yeacreate-opensources/rkwifibt.git