我一直在尝试将 Raspberry Pi 的 Ubuntu 版本从 20.04 更新到 22.04（Jammy Jellyfish）。首先，我遇到了一个错误，我的软件更新程序声称它无法连接到网络，尽管我的互联网连接正常。我从主服务器切换到美国服务器，这似乎解决了问题。
然后，在进行部分更新时（“设置新软件频道”阶段），它停止了工作，并且我收到一条很长的错误消息：
W:Target Packages (main/binary-arm64/Packages) is configured multiple times in /etc/apt/sources.list:3 and /etc/apt/sources.list:43, W:Target Packages (main/binary-i386/Packages) is configured multiple times in /etc/apt/sources.list:3 and /etc/apt/sources.list:43, W:Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:3 and /etc/apt/sources.list:43,...（为了节省空间，我删去了中间部分，因为大部分内容都大同小异）...W:Target CNF (restricted/cnf/Commands-arm64) is configured multiple times in /etc/apt/sources.list:37 and /etc/apt/sources.list:50, W:Target CNF (restricted/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:37 and /etc/apt/sources.list:50, E:Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/jammy/main/binary-i386/Packages 404 Not Found [IP: 185.125.190.36 80], E:Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/jammy-updates/main/binary-i386/Packages 404 Not Found [IP: 185.125.190.36 80], E:Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/jammy-backports/universe/binary-i386/Packages 404 Not Found [IP: 185.125.190.36 80], E:Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/jammy-security/restricted/binary-i386/Packages 404 Not Found [IP: 185.125.190.36 80], E:Some index files failed to download. They have been ignored, or old ones used instead.
错误消息远不止这些（从最开始到最后），虽然看起来大部分都是这样的，但我可能漏掉了一些重要的东西。如果需要，我可以提供完整的错误消息。
无论如何，有人能告诉我如何解决这个问题并将 Ubuntu 更新到 22.04 吗？