Debian PPC: apt update: "Err: No good signature", import through apt-key no help

Debian Sid, PPC port apt -y update Get:1 http://ftp.ports.debian.org/debian-ports sid InRelease [75.0 kB] Err:1 http://ftp.ports.debian.org/debian-ports sid InRelease No good signature Get:2 http://ftp.ports.debian.org/debian-ports unreleased InRelease [50.8 kB] Err:2 http://ftp.ports.debian.org/debian-ports unreleased InRelease No good signature Warning: GPG error: http://ftp.ports.debian.org/debian-ports sid InRelease: No good signature Error: The repository 'http://ftp.ports.debian.org/debian-ports sid InRelease' is not signed. Notice: Updating from such a repository can't be done securely, and is therefore disabled by default. Notice: See apt-secure(8) manpage for repository creation and user configuration details. Warning: GPG error: http://ftp.ports.debian.org/debian-ports unreleased InRelease: No good signature Error: The repository 'http://ftp.ports.debian.org/debian-ports unreleased InRelease' is not signed. Notice: Updating from such a repository can't be done securely, and is therefore disabled by default. Notice: See apt-secure(8) manpage for repository creation and user configuration details. Notice: Missing Signed-By in the sources.list(5) entry for 'http://ftp.ports.debian.org/debian-ports ' Notice: Missing Signed-By in the sources.list(5) entry for 'http://ftp.ports.debian.org/debian-ports ' Notice: Consider migrating all sources.list(5) entries to the deb822 .sources format Notice: The deb822 .sources format supports both embedded as well as external OpenPGP keys Notice: See apt-secure(7) for best practices in configuring repository signing The command fails because the repositories are not signed. I usually fix this by importing the key with apt-key: curl -L http://ftp.ports.debian.org/debian-ports/dists/sid/Release.gpg | sudo apt-key add - sudo: apt-key: command not found % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 1597 100 1597 0 0 14606 0 --:--:-- --:--:-- --:--:-- 14651 curl: Failed writing body root@ibmlinux:~$ I also tried to reinstall the keys. apt-get -o APT::Get::AllowUnauthenticated=true reinstall debian-archive-keyring debian-ports-archive-keyring I also tried using wget and dpkg -i: apt-get -y update Get:1 http://deb.debian.org/debian-ports sid InRelease [75.0 kB] Err:1 http://deb.debian.org/debian-ports sid InRelease No good signature Get:2 http://deb.debian.org/debian-ports unreleased InRelease [50.8 kB] Err:2 http://deb.debian.org/debian-ports unreleased InRelease No good signature Reading package lists... Done W: GPG error: http://deb.debian.org/debian-ports sid InRelease: No good signature E: The repository 'http://deb.debian.org/debian-ports sid InRelease' is not signed. 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. W: GPG error: http://deb.debian.org/debian-ports unreleased InRelease: No good signature E: The repository 'http://deb.debian.org/debian-ports unreleased InRelease' is not signed. 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. N: Missing Signed-By in the sources.list(5) entry for 'http://deb.debian.org/debian-ports ' N: Missing Signed-By in the sources.list(5) entry for 'http://deb.debian.org/debian-ports ' N: Consider migrating all sources.list(5) entries to the deb822 .sources format N: The deb822 .sources format supports both embedded as well as external OpenPGP keys N: See apt-secure(7) for best practices in configuring repository signing. This is my /etc/apt/sources.list EDIT: Finally, I found the new method for enabling gpg. vim /etc/apt/sources.list deb [signed-by=/etc/apt/trusted.gpg.d/debian-ports-archive-2025.asc] http://debian.inf.tu-dresden.de/debian-ports sid main contrib non-free non-free-firmware deb [signed-by=/etc/apt/trusted.gpg.d/debian-ports-archive-2025.asc] http://deb.debian.org/debian-ports unreleased main contrib non-free non-free-firmware But it still does not work because I cannot find the right keyring; I have tried all files of package port-keyring but still fail. EDIT2: apt reports apt 2.9.24 (ppc64) sqv reports instruction not allowed Can this the problem? EDIT3: New syntax (run apt modernize-sources to obtain it) vim /etc/apt/sources.d/debian-ports.source # Modernized from /etc/apt/sources.list Types: deb deb-src URIs: http://deb.debian.org/debian-ports/ Suites: sid Components: main contrib non-free Signed-By: /usr/share/keyrings/debian-ports-archive-keyring.gpg It still gives the errors.