ubiquity install fails at grub2

[floop]

ubiquity install fails at grub2

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubiquity 2.18.8.12
ProcVersionSignature: Ubuntu 4.2.0-27.32~14.04.1-generic 4.2.8-ckt1
Uname: Linux 4.2.0-27-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CasperVersion: 1.340.2
Date: Wed Mar 9 17:57:28 2016
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash --
LiveMediaBuild: Ubuntu 14.04.4 LTS "Trusty Tahr" - Release amd64 (20160217.1)
ProcEnviron:
 LANGUAGE=en_GB.UTF-8
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu Foundations Team Bug Bot (crichton)]

Exception during installation:
Mar 10 01:06:44 ubuntu /plugininstall.py: Traceback (most recent call last):
Mar 10 01:06:44 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1770, in <module>
Mar 10 01:06:44 ubuntu /plugininstall.py: install.run()
Mar 10 01:06:44 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 78, in wrapper
Mar 10 01:06:44 ubuntu /plugininstall.py: func(self)
Mar 10 01:06:44 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 241, in run
Mar 10 01:06:44 ubuntu /plugininstall.py: self.configure_bootloader()
Mar 10 01:06:44 ubuntu /plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1026, in configure_bootloader
Mar 10 01:06:44 ubuntu /plugininstall.py: "GrubInstaller failed with code %d" % ret)
Mar 10 01:06:44 ubuntu /plugininstall.py: ubiquity.install_misc.InstallStepError: GrubInstaller failed with code 1
Mar 10 01:06:44 ubuntu /plugininstall.py: