树莓派4使用ubuntu18.04记录

1，官网下载系统https://www.raspberrypi.org/software/operating-systems/

2，我选的是Ubuntu Desktop，我选时候是20.04和21，没有18.04了，所以找了很久，在ubuntu官网找到了ubuntu server版本18.04.5，支持树莓派2,3,4
http://cdimage.ubuntu.com/releases/18.04/release/ubuntu-18.04.5-preinstalled-server-arm64+raspi3.img.xz

3，烧录工具 https://www.balena.io/etcher/

4，烧录后，不拔出sd卡，可以看到我的电脑有boot的盘符，进去修改network-config文件（首次没启动树莓派前，如果放sd卡到树莓派，再拿出来修改，就不行）

`version: 2 ethernets:   eth0:     dhcp4: true     optional: true wifis:   wlan0:     dhcp4: true     optional: true     access-points:       "Xiaomi_60C2":         password: "yannuo88888888"`

5,如果有7寸屏幕HDMI的，要在config.txt文件末尾加入

`max_usb_current=1 hdmi_force_hotplug=1  config_hdmi_boost=10 hdmi_group=2  hdmi_mode=87  hdmi_cvt 1024 600 60 6 0 0 0`

注：如果是Raspberry Pi 4，还需要把dtoverlay=vc4-fkms-V3D注释掉。

6，插入树莓派，启动，然后应该还是不能联网，这时候，再次重启一次树莓派，就会连好了网

sudo reboot

7，换源，就是把源网址的xx.xx.com换成了mirrors.aliyun.com

`sudo vim /etc/apt/sources.list  deb http://mirrors.aliyun.com/ubuntu-ports bionic main restricted deb http://mirrors.aliyun.com/ubuntu-ports bionic-updates main restricted deb http://mirrors.aliyun.com/ubuntu-ports bionic universe deb http://mirrors.aliyun.com/ubuntu-ports bionic-updates universe deb http://mirrors.aliyun.com/ubuntu-ports bionic multiverse deb http://mirrors.aliyun.com/ubuntu-ports bionic-updates multiverse deb http://mirrors.aliyun.com/ubuntu-ports bionic-backports main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu-ports bionic-security main restricted deb http://mirrors.aliyun.com/ubuntu-ports bionic-security universe deb http://mirrors.aliyun.com/ubuntu-ports bionic-security multiverse`