Package: grub-pc Version: 2.12-9 Apparently grub-pc.postinst doesn't run grub-install for Trixie anymore. I used debootstrap to install Trixie on a spare partition of a pretty old system, told Bookworm's grub on /dev/sda1 to search for other bootable partitions and ran update-grub, booted into /dev/sda3 (Trixie), ran "dpkg-reconfigure grub-pc" as usual, but on the next reboot it still showed the old grub menu found on /dev/sda1.
I had to manually run grub-install. Regards Harri
