grub-install doesn't detect 32 bit EFI environment correctly

Wily installer can't cope with 32 bit EFI on Baytrail-T systems, I think it tries to install grub for i386-pc instead and fails.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: ubiquity 2.21.37 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.1-0ubuntu3
Architecture: amd64
CasperVersion: 1.365
Date: Sun Feb 14 13:55:58 2016
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
ProcEnviron:
 LANGUAGE=en_AU.UTF-8
 PATH=(custom, no user)
 LANG=en_AU.UTF-8
 SHELL=/bin/bash
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)