apt-get update

[hdk]

apt-get update problems:

W: http://ppa.launchpad.net/ayufan/rock64-0.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
E: The repository 'http://ppa.launchpad.net/kupfer-team/ppa/ubuntu bionic 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.
W: http://ppa.launchpad.net/ayufan/rock64-0.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ports.ubuntu.com/ubuntu-ports/dis.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ppa.launchpad.net/gerardpuig/ppa/.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ports.ubuntu.com/ubuntu-ports/dis.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://deb.ayufan.eu/orgs/ayufan-rock64/.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://repo.steampowered.com/steam/dists.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ports.ubuntu.com/ubuntu-ports/dis.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ppa.launchpad.net/oguzhaninan/sta.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ppa.launchpad.net/utappia/stable/.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.

[ventus_orientis]

apt-get update problems:

W: http://ppa.launchpad.net/ayufan/rock64-0.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
E: The repository 'http://ppa.launchpad.net/kupfer-team/ppa/ubuntu bionic 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.
W: http://ppa.launchpad.net/ayufan/rock64-0.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ports.ubuntu.com/ubuntu-ports/dis.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ppa.launchpad.net/gerardpuig/ppa/.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ports.ubuntu.com/ubuntu-ports/dis.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://deb.ayufan.eu/orgs/ayufan-rock64/.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://repo.steampowered.com/steam/dists.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ports.ubuntu.com/ubuntu-ports/dis.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ppa.launchpad.net/oguzhaninan/sta.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.
W: http://ppa.launchpad.net/utappia/stable/.../InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/ayufan.key.chroot.gpg are ignored as the file has an unsupported filetype.

I get these errors as well but updates seem to work despite this

[hdk]

I removed the unsupported ayufan.key.chroot.gpg.