Connecting an Raspberry PI to the eduroam or campusroam wifi network results in intermittent connections on Raspbian Buster. Following tutorial explains how to fix this issue, but a working internet connection is required!

Add one of the following lines to your '/etc/apt/sources.list' file. Comment previously existing 'deb' lines with '#'

deb http://raspbian.raspberrypi.org/raspbian/ stretch main contrib non-free rpi
deb http://raspbian.raspberrypi.org/raspbian/ jessie main contrib non-free rpi
#Note: copy pasting in a terminal using the keyboard shortcuts requires an additional 'shift' --> 'ctrl + shift + c' or 'ctrl + shift + v'

Full example:

sudo nano /etc/apt/sources.list #press enter to open the file
deb http://raspbian.raspberrypi.org/raspbian/ stretch main contrib non-free rpi # paste this line using 'ctrl + shift + v'
# Comment out the previously existing lines for certainty --> use the '#' character to comment out lines.
# press 'ctrl + o' to save the file.
# press 'ctrl + x' to exit nano.