Iirc when I had this problem I solved it by first 1)booting to a live cd
2) chrooting to the new system
3) installing crypt-setup AND lvm
4) doing the update ramfs thing
5) rebooting
The main problem I had was upgrading did not detect the need for the lvm and encryption packages and update the boot kernel modules accordingly. Instead it treated it as a regular install/upgrade without encrypted hard drives.
Iirc when I had this problem I solved it by first 1)booting to a live cd
2) chrooting to the new system
3) installing crypt-setup AND lvm
4) doing the update ramfs thing
5) rebooting
The main problem I had was upgrading did not detect the need for the lvm and encryption packages and update the boot kernel modules accordingly. Instead it treated it as a regular install/upgrade without encrypted hard drives.