Samsung M2020 Printer in Ubuntu

SULDR files from https://www.bchemnet.com/suldr/

Download the Keyring File https://www.bchemnet.com/suldr/pool/debian/extra/su/suldr-keyring_2_all.deb.

Install it

wget https://www.bchemnet.com/suldr/pool/debian/extra/su/suldr-keyring_2_all.deb
sudo dpkg -i suldr-keyring_2_all.deb
sudo apt update
sudo apt install suld-driver2-1.00.39

Official packages from HP

Download the ULD from https://support.hp.com/us-en/drivers/selfservice/swdetails/samsung-xpress-sl-m2021-laser-printer-series/16462598/swItemId/fp-194243-2

sudo tar -xvf uld_V1.00.39_01.17.tar.gz 
sudo chmod -R  777 uld
cd uld
sudo ./install.sh

Press Enter till you reach Point 10 of the license agreement. It is just 2-3 lines and then you will exit the installer if you press exist once more. Therefore be careful.