I have two installations of debian on a single hard drive. One is on ext4 partition and the other is on luks partition. I first installed debian on the ext4 partition and then on luks partition.
Recently I did "sudo apt upgrade" on the debian on ext4. Since then I cannot boot into the debian on luks partition as the option to choose this installation do not appear on the starting screen. I tried to solve this by posting this question Adding debian installed on LUKS partition to boot option . But the answer didn't solve the problem.
However, the answer suggested me to "write a custom GRUB configuration entry for it in /etc/grub.d/40_custom, which will be included into /boot/grub/grub.cfg generated by update-grub".
Since the luks partition is encrypted I am having trouble doing so. So can anyone help?