diff --git a/vms/autoinstall/stretch-winterfell.cfg b/vms/autoinstall/stretch-winterfell.cfg
index 5806765..13080f4 100644
--- a/vms/autoinstall/stretch-winterfell.cfg
+++ b/vms/autoinstall/stretch-winterfell.cfg
@@ -1,46 +1,47 @@
 d-i debian-installer/locale string en_US
 d-i console-keymaps-at/keymap select us
 d-i netcfg/choose_interface select auto
 d-i netcfg/get_hostname kolab.example.org
 d-i netcfg/get_domain kolab.example.org
 d-i netcfg/wireless_wep string
 d-i mirror/country string enter information manually
 d-i mirror/http/hostname string ftp.debian.org
 d-i mirror/http/directory string /debian
 d-i clock-setup/utc boolean true
 d-i time/zone string Europe/Zurich
 d-i clock-setup/ntp boolean false
 
 d-i partman-auto/disk string /dev/sda
 d-i partman-auto/method string lvm
 d-i partman-auto/choose_recipe select atomic
 d-i partman-lvm/confirm boolean true
 d-i partman-lvm/device_remove_lvm boolean true
 d-i partman-lvm/confirm_nooverwrite boolean true
 d-i partman/choose_partition select finish
 d-i partman-partitioning/confirm_write_new_label boolean true
 d-i partman/choose_partition select finish
 d-i partman/confirm boolean true
 d-i partman/confirm_nooverwrite boolean true
 
 d-i passwd/root-password password Welcome2KolabSystems
 d-i passwd/root-password-again password Welcome2KolabSystems
 
 d-i passwd/user-fullname string Kolab Systems User
 d-i passwd/username string developer
 d-i passwd/user-password password Welcome2KolabSystems
 d-i passwd/user-password-again password Welcome2KolabSystems
 
 d-i apt-setup/non-free boolean true
 d-i apt-setup/contrib boolean true
 
 tasksel tasksel/first multiselect standard
 d-i pkgsel/include select openssh-server sysv-rc-conf wget
 d-i popularity-contest/participate boolean false
 
 d-i grub-installer/only_debian boolean true
 d-i grub-installer/with_other_os boolean true
+d-i grub-installer/bootdev string /dev/sda
 
 d-i preseed/late_command string in-target wget -q -O/root/init.sh http://cgit.kolab.org/stick/plain/vms/autoinstall/bootstrap/bootstrap-stretch-winterfell-script.txt; in-target chmod +x /root/init.sh; in-target bash /root/init.sh
 
 d-i finish-install/reboot_in_progress note