Attached patch for /usr/sbin/mkinitramfs fixes the problem.
-- Ondrej 'Santiago' Zajicek (email: santi...@crfreenet.org)
--- old/mkinitramfs 2015-04-26 19:41:31.886358308 +0200 +++ new/mkinitramfs 2015-04-26 19:07:04.000000000 +0200 @@ -183,6 +183,7 @@ export KEYMAP export MODULES export BUSYBOX +export CRYPTSETUP # Private, used by 'catenate_cpiogz'. export __TMPCPIOGZ