ROS2安装ros-humble-usb-cam遇到404错误导致安装失败，如图：

解决方法：

备份 sources.list

sudo cp /etc/apt/sources.list.d/ros2.list /etc/apt/sources.list.d/ros2.list.bak

替换为清华源

sudo sed -i 's|http://packages.ros.org/ros2/ubuntu|https://mirrors.tuna.tsinghua.edu.cn/ros2/ubuntu|g' /etc/apt/sources.list.d/ros2.list

更新并重新安装

sudo apt update
sudo apt install ros-humble-usb-cam