sudo apt update输入终端后，我得到以下输出：
Hit:1 http://ftp.hu.debian.org/debian buster InRelease
Ign:2 http://ftp.hu.debian.org/debian buster/updates InRelease
Hit:3 http://ftp.hu.debian.org/debian buster-updates InRelease
Err:4 http://ftp.hu.debian.org/debian buster/updates Release
404 Not Found [IP: 195.228.252.133 80]
Reading package lists... Done
E: The repository 'http://ftp.hu.debian.org/debian buster/updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
因此，我根本无法更新我的系统。我使用的是 Debian 10.5 KDE。我安装了debian-live-10.5.0-amd64-kde+nonfree.iso
答案1
该错误不应该防止你免于升级；其他存储库仍在更新。apt upgrade应该允许你升级。
然而，“buster/updates”在主存储库中并不存在，因此您不妨将其删除；编辑/etc/apt/sources.list并删除该ftp.hu.debian.org/debian buster/updates行。当你这样做时，检查你是否有一行security.debian.org——我怀疑错误buster/updates来自于对此所做的更改：
deb http://security.debian.org buster/updates main
您的/etc/apt/sources.list文件最终应如下所示：
deb http://ftp.hu.debian.org/debian/ buster main non-free contrib
deb-src http://ftp.hu.debian.org/debian/ buster main non-free contrib
deb http://security.debian.org/ buster/updates main contrib non-free
deb-src http://security.debian.org/ buster/updates main contrib non-free
deb http://ftp.hu.debian.org/debian/ buster-updates main contrib non-free
deb-src http://ftp.hu.debian.org/debian/ buster-updates main contrib non-free