记更换树莓派4B的国内软件源

 建议修改之前先备份好修改的文件，方便回滚

# /etc/apt/sources.list.d/raspi.list

# 清华 
# deb https://mirrors.tuna.tsinghua.edu.cn/raspberrypi/ jessie main

# 清华 
# deb https://mirrors.tuna.tsinghua.edu.cn/raspberrypi/ stretch main

# 中科大 
deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/ jessie main

# 中科大 
deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/ stretch main

# /etc/apt/sources.list

# 清华 
# deb https://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi

# 清华 
# deb https://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ jessie main contrib non-free rpi

# 中科大 
deb http://mirrors.ustc.edu.cn/raspbian/raspbian/ jessie main contrib non-free rpi

# 中科大 
deb http://mirrors.ustc.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi

附：树莓派软件源大全 

https://www.raspbian.org/RaspbianMirrors