Can't install grub on surface pro

Installing the bootloader on efi partition (/dev/sda2) fails.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: ubiquity 2.19.8 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 3.16.0-20.27-generic 3.16.3
Uname: Linux 3.16.0-20-generic x86_64
ApportVersion: 2.14.7-0ubuntu3
Architecture: amd64
CasperVersion: 1.344
Date: Thu Oct 9 19:46:44 2014
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash --
LiveMediaBuild: Ubuntu 14.10 "Utopic Unicorn" - Alpha amd64 (20141006)
ProcEnviron:
 LANGUAGE=it_IT.UTF-8
 PATH=(custom, no user)
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)