编辑/etc/apt/sources.list，内容为

deb http://ftp.us.debian.org/debian/ wheezy main

deb-src http://ftp.us.debian.org/debian/ wheezy main

deb http://security.debian.org/ wheezy/updates main

deb-src http://security.debian.org/ wheezy/updates main

wheezy-updates, previously known as ‘volatile’

deb http://ftp.us.debian.org/debian/ wheezy-updates main

deb-src http://ftp.us.debian.org/debian/ wheezy-updates main

运行

apt-get update

apt-get dist-upgrade

重新启动即可

如果报gpg错误可能要先运行

apt-get install debian-archive-keyring