1、下载64位的raspbian
下载安装时注意你的派是否支持64位
https://downloads.raspberrypi.org/raspios_arm64/images/
2、换成国内源（亲测是可以支持64位的源）：
把/etc/apt/sources.list所有内容替换为：
deb http://mirrors.tuna.tsinghua.edu.cn/debian buster main contrib non-free deb http://mirrors.tuna.tsinghua.edu.cn/debian-security/ buster/updates main contrib non-free deb http://mirrors.tuna.tsinghua.edu.cn/debian buster-updates main contrib non-free # Uncomment deb-src lines below then 'apt-get update' to enable 'apt-get source' #deb-src http://mirrors.tuna.tsinghua.edu.cn/debian buster main contrib non-free #deb-src http://mirrors.tuna.tsinghua.edu.cn/debian-security/ buster/updates main contrib non-free #deb-src http://mirrors.tuna.tsinghua.edu.cn/debian buster-updates main contrib non-free
然后在把/etc/apt/sources.list.d/raspi.list所有内容替换为：
deb http://mirrors.tuna.tsinghua.edu.cn/raspberrypi/ buster main ui # Uncomment line below then 'apt-get update' to enable 'apt-get source' #deb-src http://mirrors.tuna.tsinghua.edu.cn/raspberrypi/ buster main ui
4.更新
sudo apt-get update sudo apt-get upgrade