树莓派源的更新

1 备份软件更新源
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
sudo cp /etc/apt/sources.list.d/raspi.list /etc/apt/sources.list.d/raspi.list.bak
2 修改软件源
编辑文件
sudo nano /etc/apt/sources.list

deb http://mirrordirector.raspbian.org/raspbian/ jessie main contrib non-free rpi
#Uncomment line below then ‘apt-get update’ to enable ‘apt-get source’
deb-src http://archive.raspbian.org/raspbian/ jessie main contrib non-free rpi
deb http://mirrors.aliyun.com/raspbian/raspbian/ jessie main non-free contrib
deb-src http://mirrors.aliyun.com/raspbian/raspbian/ jessie main non-free contrib
deb http://mirrors.neusoft.edu.cn/raspbian/raspbian/ jessie main contrib non-free rpi
deb-src http://mirrors.neusoft.edu.cn/raspbian/raspbian/ jessie main contrib non-free rpi
deb http://mirrordirector.raspbian.org/raspbian/ jessie main contrib non-free rpi
deb-src http://mirrordirector.raspbian.org/raspbian/ jessie main contrib non-free rpi

然后使用 Ctrl+O 回车后保存文件，Ctrl+X 退出编辑器。
编辑文件raspi.list
sudo nano /etc/apt/sources.list.d/raspi.list
更新后的raspi.list为

deb http://archive.raspberrypi.org/debian/ jessie main ui

Uncomment line below then ‘apt-get update’ to enable ‘apt-get source’

deb-src http://archive.raspberrypi.org/debian/ jessie main ui

use ustc mirror:

deb http://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian/ jessie main ui

实际修改是，将archive.raspberrypi.org替换为mirrors.ustc.edu.cn/archive.raspberrypi.org。