I met the problem Download Boot faild
when i use AndroidTool_Release_v2.71 to flash new OS with windows.
you can solve the problem.
#####push the reset button on your rockchip product then RUN(执行)again.
Source
https://dev.t-firefly.com/thread-12148-1-1.html
If you get another bug you can download latest version(2.71 or more) of AndroidTool_Release for rockchip product
https://github.com/rockchip-linux/tools