When run with an lvm setup, ubiquity attempts to install grub to /dev/mapper

[Max Brustkern]

I'm running the automated desktop ISO tests, which haven't changed in a while. The lvm install test most recently passed on December 11 on amd64 and December 12 on i386. When I look at it now, grub-install is attempting to run on /dev/mapper. This is the initial preseed without the header:

d-i debian-installer/locale string en_US.UTF-8
d-i netcfg/get_hostname string utah-example
d-i partman-auto/method string lvm
#need this for desktop
d-i partman/choose_partition select Finish partitioning and write changes to disk
#need this for cobbler
d-i partman/confirm boolean true
#need this for non-desktop
d-i partman/confirm_nooverwrite boolean true
d-i time/zone string Etc/UTC
d-i passwd/user-fullname string UTAH
d-i passwd/username string utah
d-i passwd/user-password password !ubuntu123
d-i passwd/user-password-again password !ubuntu123
d-i pkgsel/include string openssh-server python-yaml bzr git gdebi-core
#need this for non-desktop
d-i finish-install/reboot_in_progress note
#Temporary workaround for LP:1258245
d-i preseed/early_command string chmod 666 /dev/ttyS0
d-i preseed/late_command string chroot /target /usr/sbin/usermod -G dialout syslog

Some of that (mostly late_command) is modified by utah, so I can retrieve the full one if necessary.

[Max Brustkern (nuclearbob)]

The only difference between this and the default preseed (which installs correctly) is that d-i partman-auto/method string is changed from regular to lvm. If I do a manual lvm install, it works, so this appear to be a problem interpreting that preseed directive.

[Max Brustkern (nuclearbob)]

Not sure if this is related or a separate bug, but when I do a manual install and select encryption, grub fails to install to /dev/vda. When doing a preseeded install, the install finishes but the system never boots.

[Max Brustkern (nuclearbob)]

This is still affecting the final beta images, as of yesterday, confirmed via automatic and manual testing.