apt -t buster-backports install 처럼 백포트에서 설치한다는 옵션이 필요하다.apt 명령의 경우 backports 에 적용할 때는 -t xxx-backports를 주면 된다./etc/apt/sources.list 의 main 뒤에 contrib, non-free를 붙여주면 된다.# bullseye 기준 deb http://deb.debian.org/debian bullseye main contrib non-free deb-src http://deb.debian.org/debian bullseye main contrib non-free deb http://deb.debian.org/debian-security/ bullseye-security main contrib non-free deb-src http://deb.debian.org/debian-security/ bullseye-security main contrib non-free deb http://deb.debian.org/debian bullseye-updates main contrib non-free deb-src http://deb.debian.org/debian bullseye-updates main contrib non-free # backports 에 대해서도 필요하면 deb http://deb.debian.org/debian bullseye-backports main contrib non-free deb-src http://deb.debian.org/debian bullseye-backports main contrib non-free