The root of the problem is that the Debian installer does not install package cryptsetup-initramfs.
- Bug#941319: debian-installer: Volume group 'LVM1' not ... Heinrich Schuchardt
- Bug#941319: debian-installer: Volume group 'LVM1'... Heinrich Schuchardt
- Bug#941319: debian-installer: Volume group 'LVM1'... Heinrich Schuchardt