I originally had a problem installing packages on a Raspberry Pi 2 Model A with an older version of Raspbian. So downloaded the July 2019 of Raspbian Buster Lite, and it installed ok. But it has the same problem with installs:
sudo apt update Get:1 http://raspbian.raspberrypi.org/raspbian buster InRelease Get:2 http://archive.raspberrypi.org/debian buster InRelease Err:1 http://raspbian.raspberrypi.org/raspbian buster InRelease Undetermined Error [IP: 192.168.1.254 80] Err:2 http://archive.raspberrypi.org/debian buster InRelease Undetermined Error [IP: 192.168.1.254 80]
and it when I try to install packages it cannot find them. For example
sudo apt install python-pip Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package python-pip
It's on Wifi and it can fetch webpages with wget. I have tried
sudo apt update --allow-releaseinfo-change
but it doesn't help.