cd /etc/apt/
sudo cp sources.list sources.list.bak
sudo sed -i "s?http://deb.debian.org?https://mirrors.ustc.edu.cn?" sources.list
sudo sed -i "s?http://security.debian.org?https://mirrors.ustc.edu.cn?" sources.list
cd sources.list.d/
sudo cp raspi.list raspi.list.bak
sudo sed -i "s?http://archive.raspberrypi.org?https://mirrors.ustc.edu.cn/raspberrypi?" raspi.list