the log from the update:
nvidia@tegra-ubuntu:~$ sudo apt update
Get:1 https://repo.download.nvidia.com/jetson/common r35.1 InRelease [2555 B]
Get:2 https://repo.download.nvidia.com/jetson/t234 r35.1 InRelease [2550 B]
Err:1 https://repo.download.nvidia.com/jetson/common r35.1 InRelease
The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0D296FFB880FB004
Hit:3 Index of /ubuntu-ports focal InRelease
Hit:4 Index of /ubuntu-ports focal-updates InRelease
Err:2 https://repo.download.nvidia.com/jetson/t234 r35.1 InRelease
The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0D296FFB880FB004
Hit:5 Index of /ubuntu-ports focal-security InRelease
Reading package lists… Done
W: GPG error: https://repo.download.nvidia.com/jetson/common r35.1 InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0D296FFB880FB004
E: The repository ‘https://repo.download.nvidia.com/jetson/common r35.1 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: https://repo.download.nvidia.com/jetson/t234 r35.1 InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 0D296FFB880FB004
E: The repository ‘https://repo.download.nvidia.com/jetson/t234 r35.1 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: Target Packages (main/binary-arm64/Packages) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target DEP-11 (main/dep11/Components-arm64.yml) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:1
W: Target Packages (main/binary-arm64/Packages) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
W: Target DEP-11 (main/dep11/Components-arm64.yml) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
W: Target DEP-11-icons-small (main/dep11/icons-48x48.tar) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list.d/nvidia-l4t-apt-source.list:2
nvidia@tegra-ubuntu:~$ sudo apt install nvidia-jetpack
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package nvidia-jetpack