Following your instructions and chrooted into the filesystem I have an issue. Haven't really done this before - I assume I missed something basic?
root@john-VirtualBox:/# apt update
Get:1 http://ports.ubuntu.com/ubuntu-ports bionic InRelease [242 kB]
Err:1 http://ports.ubuntu.com/ubuntu-ports bionic InRelease
Couldn't create temporary file /tmp/apt.conf.dK8U7t for passing config to apt-key
Get:2 http://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease [88.7 kB]
Err:2 http://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease
Couldn't create temporary file /tmp/apt.conf.BBHSEz for passing config to apt-key
Get:3 http://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease [74.6 kB]
Err:3 http://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease
Couldn't create temporary file /tmp/apt.conf.hsZwdH for passing config to apt-key
Get:4 http://ports.ubuntu.com/ubuntu-ports bionic-security InRelease [88.7 kB]
Err:4 http://ports.ubuntu.com/ubuntu-ports bionic-security InRelease
Couldn't create temporary file /tmp/apt.conf.fwFtHU for passing config to apt-key
Reading package lists... Done
W: GPG error: http://ports.ubuntu.com/ubuntu-ports bionic InRelease: Couldn't create temporary file /tmp/apt.conf.dK8U7t for passing config to apt-key
E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic 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://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease: Couldn't create temporary file /tmp/apt.conf.BBHSEz for passing config to apt-key
E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic-updates 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://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease: Couldn't create temporary file /tmp/apt.conf.hsZwdH for passing config to apt-key
E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic-backports 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://ports.ubuntu.com/ubuntu-ports bionic-security InRelease: Couldn't create temporary file /tmp/apt.conf.fwFtHU for passing config to apt-key
E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic-security 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.
Following your instructions and chrooted into the filesystem I have an issue. Haven't really done this before - I assume I missed something basic?
root@john-VirtualBox:/# apt update Get:1 http://ports.ubuntu.com/ubuntu-ports bionic InRelease [242 kB] Err:1 http://ports.ubuntu.com/ubuntu-ports bionic InRelease Couldn't create temporary file /tmp/apt.conf.dK8U7t for passing config to apt-key Get:2 http://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease [88.7 kB] Err:2 http://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease Couldn't create temporary file /tmp/apt.conf.BBHSEz for passing config to apt-key Get:3 http://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease [74.6 kB] Err:3 http://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease Couldn't create temporary file /tmp/apt.conf.hsZwdH for passing config to apt-key Get:4 http://ports.ubuntu.com/ubuntu-ports bionic-security InRelease [88.7 kB] Err:4 http://ports.ubuntu.com/ubuntu-ports bionic-security InRelease Couldn't create temporary file /tmp/apt.conf.fwFtHU for passing config to apt-key Reading package lists... Done W: GPG error: http://ports.ubuntu.com/ubuntu-ports bionic InRelease: Couldn't create temporary file /tmp/apt.conf.dK8U7t for passing config to apt-key E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic 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://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease: Couldn't create temporary file /tmp/apt.conf.BBHSEz for passing config to apt-key E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic-updates 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://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease: Couldn't create temporary file /tmp/apt.conf.hsZwdH for passing config to apt-key E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic-backports 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://ports.ubuntu.com/ubuntu-ports bionic-security InRelease: Couldn't create temporary file /tmp/apt.conf.fwFtHU for passing config to apt-key E: The repository 'http://ports.ubuntu.com/ubuntu-ports bionic-security 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.