Just did a fresh install of latest Ubuntu 26.04 Gnome build on a Pine Quartz64 A board.
After an `apt update` running `apt upgrade` tries to update the `linux-libc-dev` package, which is downloaded from `ports.ubuntu.com`. However it consistently fails with a 404.
Digging around a little, it seems like this package should match the kernel that's in use, so is the underlying problem that `apt` is trying to download it from the ubuntu repo instead of the armbian one where the kernel package comes from? I have not modified any apt configuration since installing.