Jetson Xavier NX apt更换国内源

在xavier NX板子上安装软件包的时候，网速特别慢，于是想更换源，网上找到了如下博客，验证可用。

原文地址 https://blog.csdn.net/darnell888/article/details/106644437

本文主要讲述，基于 Jetson Xavier NX 开发者套件apt更换国内源。

What is Jetson Xavier NX ：

•  NVIDIA® Jetson Xavier™ NX 是体型超小的AI超级计算机，适用于嵌入式系统和边缘系统。
•  高达 21 TOPS 加速计算能力，可以并行运行现代神经网络并处理来自多个高分辨率传感器的数据。
•  Jetson Xavier NX 是生产就绪型产品，可支持所有热门 AI 框架。
• 更换国内源比较简单，但是有的同学可能没有注意一些细节，即PC虚拟机和ARM核ubuntu系统更换源的差异，导致提示 E: Failed to fetch http://…，例如下所示：

E: Failed to fetch http://mirrors.aliyun.com/ubuntu/dists/bionic/main/binary-arm64/Packages  404  Not Found [IP: 120.223.240.248 80]
E: Failed to fetch http://mirrors.aliyun.com/ubuntu/dists/bionic-security/main/binary-arm64/Packages  404  Not Found [IP: 120.223.240.248 80]
E: Failed to fetch http://mirrors.aliyun.com/ubuntu/dists/bionic-updates/main/binary-arm64/Packages  404  Not Found [IP: 120.223.240.248 80]
E: Failed to fetch http://mirrors.aliyun.com/ubuntu/dists/bionic-proposed/main/binary-arm64/Packages  404  Not Found [IP: 120.223.240.248 80]
E: Failed to fetch http://mirrors.aliyun.com/ubuntu/dists/bionic-backports/main/binary-arm64/Packages  404  Not Found [IP: 120.223.240.248 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.

需要搞清楚的是：

1. Jetson Xavier NX 默认系统是 Ubuntu18.04LTS，对应源关键字：“bionic”
2. Jetson Xavier NX CPU是arm64的架构，镜像路径：xxx/ubuntu-ports/

因此，Jetson Xavier NX 更换源的步骤为：
(1) root权限，重新编辑source.list文件

sudo vim /etc/apt/sources.list

(2)更换内容为（用的是清华源，也可以搜索其他的源）：

deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-updates main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-updates main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-security main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-security main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-backports main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-backports main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial main universe restricted
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial main universe restricted

(3)更新源

sudo apt-get update

以上就完成了 Jetson Xavier NX 的apt源更新，下载速度会大幅提升.