The ramdisk image for Firefly-RK3288 board and other rockchip based platforms.
After cloning, cd to the working directory, and run:
make
a new initrd.img will be created in the parent directory.
Based on https://github.com/radxa/initrd.git which is based on https://github.com/Galland/rk30_linux_initramfs which is based on fkubi's initramfs who in turn based on Debian's initramfs.cpio.