> Whoa, don't do that: it puts you on the path to a Frankendebian. > https://wiki.debian.org/DontBreakDebian
Luckily I knew something was wrong with that approach, and I did some research about adding and pinning new repositories, so that I can install lilypond from the testing repository with $ sudo apt install -t testing lilypond and making sure that the testing repository is not used for anything if apt is doing its thing automatically. > The following packages have unmet dependencies: > lilypond : Depends: lilypond-data (= 2.20.0-2) but > 2.19.81+really-2.18.2-13+deb10u1 is to be installed > Depends: libc6 (>= 2.29) but 2.28-10 is to be installed² > Depends: libcrypt1 (>= 1:4.1.0) but it is not installable > Depends: libgcc-s1 (>= 3.0) but it is not installable I tried to install lilypond with a --dry-run and in fact I get a different error: The following packages have unmet dependencies: libc6-dev : Breaks: libgcc-8-dev (< 8.4.0-2~) but 8.3.0-6+rpi1 is to be installed but I guess this is due to my system having different packages installed than yours (although, it does seem strange that neither of libc6-dev or libgcc-8-dev seem to be in the recursive dependencies of lilypond...) > My own solution would be to consider either dual-booting the Pi4 > with buster and bullseye (I always set my disks up with two root > filesystems), or acquiring a second Pi. Sadly, that's not an option for me, since I'm using lilypond together with other software installed on my Pi. I would have to install a different OS altogether, which would be quite annoying. If the path of installing debs is totally closed, is it possible to make my own build? Cheers, renyhp