Raspberry Pi ubuntu20.10 system switch domestic source
There is a lot of information about domestic source switching on the Internet, whether it is Ali source, Tsinghua source, or other sources, you need to pay attention to switching ubuntu in the source link to ubuntu - ports
#aliyun
deb http://mirrors.aliyun.com/ubuntu-ports/ focal main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu-ports/ focal-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu-ports/ focal-backports main restricted universe multiverse