Hi hwlim3unws, I had a similar issue on my Drive AGX Xavier.
If you can ping out to the internet then I think this is just an apt issue. My Settings GUI looked the same as yours, but I could still connect to the internet.
Could you post the output of this command, run on Xavier A?
$ cat /etc/apt/sources.list
There may be no output – in my case that file was empty. Below are the intended contents of that file:
# Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
# NVIDIA CORPORATION and its licensors retain all intellectual property
# and proprietary rights in and to this software, related documentation
# and any modifications thereto. Any use, reproduction, disclosure or
# distribution of this software and related documentation without an express
# license agreement from NVIDIA CORPORATION is strictly prohibited.
# Recommended mirrors default, -updates, -security, Components main restricted & universe enabled
deb http://ports.ubuntu.com/ubuntu-ports/ bionic main universe restricted
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-updates main universe restricted
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security main universe restricted
# Backports https://wiki.ubuntu.com/UbuntuBackports not recommended
# deb http://ports.ubuntu.com/ubuntu-ports/ bionic-backports main universe restricted
# Proposed https://wiki.ubuntu.com/Testing/EnableProposed not recommended
# deb http://ports.ubuntu.com/ubuntu-ports/ bionic-proposed main universe restricted
# Multiverse components have copyright or legal issues use with (legal) care
# deb http://ports.ubuntu.com/ubuntu-ports/ bionic multiverse
# deb http://ports.ubuntu.com/ubuntu-ports/ bionic-updates multiverse
# deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security multiverse
If you update /etc/apt/sources.list so it contains the text above, “sudo apt update” should work (as long as you have an internet connection). And you won’t need to run apt-add-repository, since the sources.list already contains the repositories you were trying to add.
I posted about my issue with /etc/apt/sources.list here: https://devtalk.nvidia.com/default/topic/1072499/general/empty-etc-apt-sources-list-on-clean-drive-os-5-1-6-1-image/?offset=10#5434084
Note, if you want to use “apt-add-repository” anyway, you’ll need to install it:
$ sudo apt-get install software-properties-common
Hope that helps!