硬件：Raspberry Pi 4B
系統：Ubuntu 19.10 (Eoan Ermine) for IOT
官網：https://ubuntu.com/download/iot/raspberry-pi
配置步驟
1. 下載系統鏡像
http://cdimage.ubuntu.com/releases/19.10/release/ubuntu-19.10-preinstalled-server-arm64+raspi3.img.xz
2. 燒錄至SD卡進行系統安裝
3. 系統登陸
默認賬號：ubuntu
默認密碼：ubuntu
4. 更換鏡像源
4.1 備份 apt 源文件
sudo cp -p /etc/apt/sources.list /etc/apt/sources.list.bak
4.2 編輯 apt 源文件，更新為國內鏡像源
注意：路徑節點不是 ubuntu，而是 ubuntu-ports
注意：系統版本號為 Ubuntu 19.10，對應代號為 eoan
注意：系統版本號為 Ubuntu 20.04，對應代號為 focal
sudo nano /etc/apt/sources.list
#阿里雲源 deb http://mirrors.aliyun.com/ubuntu-ports eoan main restricted deb http://mirrors.aliyun.com/ubuntu-ports eoan-updates main restricted deb http://mirrors.aliyun.com/ubuntu-ports eoan universe deb http://mirrors.aliyun.com/ubuntu-ports eoan-updates universe deb http://mirrors.aliyun.com/ubuntu-ports eoan multiverse deb http://mirrors.aliyun.com/ubuntu-ports eoan-updates multiverse deb http://mirrors.aliyun.com/ubuntu-ports eoan-backports main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu-ports eoan-security main restricted deb http://mirrors.aliyun.com/ubuntu-ports eoan-security universe deb http://mirrors.aliyun.com/ubuntu-ports eoan-security multiverse
5. 安裝桌面環境（可選擇：xubuntu-desktop、lubuntu-desktop、kubuntu-desktop）
sudo apt-get install xubuntu-desktop
6. 重啟系統
sudo reboot
異常情況
如果 #5 apt-get 安裝出錯如下，可以恢復為 ubuntu 官方源進行安裝。
Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies:
參考資料
https://ubuntu.com/download/iot
https://opsx.alibaba.com/mirror
https://mirrors.ustc.edu.cn/