树莓派在国内更新软件源很慢，可以更换为国内的软件源。
1、更新/etc/apt/sources.list
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bk
sudo nano /etc/apt/sources.list替换为以下内容（或者注释之前的，然后追加）
# ARM(32位系统)
deb http://mirrors.ustc.edu.cn/raspbian/raspbian/ bullseye main contrib non-free rpi
# deb-src http://mirrors.ustc.edu.cn/raspbian/raspbian/ bullseye main contrib non-free rpi
# ARM64(64位系统)
# Arm64 架构的 Raspberry Pi OS 仍处于 beta 状态，中科大源亦不含此架构。对于 arm64 的 Raspberry Pi OS，可以直接使用 arm64 Debian 的源（以 Bullseye 示例）：
deb https://mirrors.ustc.edu.cn/debian/ bullseye main contrib non-free
# deb-src http://mirrors.ustc.edu.cn/debian bullseye main contrib non-free
deb https://mirrors.ustc.edu.cn/debian/ bullseye-updates main contrib non-free
# deb-src http://mirrors.ustc.edu.cn/debian bullseye-updates main contrib non-free
deb https://mirrors.ustc.edu.cn/debian-security bullseye-security main contrib non-free
# deb-src http://mirrors.ustc.edu.cn/debian-security/ bullseye-security main non-free contrib
2、更新/etc/apt/sources.list.d/raspi.list
sudo nano /etc/apt/sources.list.d/raspi.list替换为以下内容（或者注释之前的，然后追加）
# ARM(32位系统)
deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian/ bullseye main
#deb-src https://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian/ bullseye main
# ARM64(64位系统)
deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian/ bullseye main
#deb-src https://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian/ bullseye main
3、更新
依次输入以下命令进行更新。
sudo apt update && sudo apt dist-upgrade如果需要单独更新EEPROM可以参考：传送门
如果apt update出现错误：The following signatures couldn't be verified because the public key is not available: NO_PUBKEY xxxxxxxxxxxxxxxxxxx
使用以下命令添加KEY：
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com xxxxxxxxxxxxxxxxxxx
文章评论
树莓派64位换源以后可能下不了软件，想知道博主有没有解决的办法
@Billion 64位镜像可以直接使用debian的系统源，首先需要编辑/etc/apt/sources.list，使用#号注释原内容，然后在末尾添加Debian的系统源：
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ buster main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ buster main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-updates main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-updates main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-backports main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-backports main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian-security buster/updates main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security buster/updates main contrib non-free
接着需要配置树莓派官方的软件源，编辑/etc/apt/sources.list.d/raspi.list，同样的，注释原内容，在末尾添加如下内容：
deb http://mirrors.tuna.tsinghua.edu.cn/raspberrypi/ buster main ui
系统源和软件源配置完成以后，使用下述两条命令更新：
sudo apt update
sudo apt upgrade -y