Grub thinks it is 32 bit when it is 64 bit

[rserra]

Installing Lubuntu on Asus T100

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: Tue Feb 2 16:10:44 2016
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/lubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Lubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Phillip Susi (psusi)]

It looks like grub has decided it is 32 bit even though it is not:

grub-install: error: /usr/lib/grub/i386-pc/modinfo.sh doesn't exist. Please specify --target or --directory.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Alberto Salvia Novella (es20490446e)]

Please:

1. Edit this report description, so it explains the actual consequences of this bug.
2. Set this report status back to "confirmed".

Thank you.

[Phillip Susi (psusi)]

It's an apport automatically filed bug of the installer crashing. Should be pretty evident.

[Magosányi Árpád (mag-magwas)]

A t100ta can be made to be bootable by installing grub-efi-ia32 (as the efi subsystem is actually 32 bit). See http://www.jfwhome.com/2016/01/04/latest-steps-to-install-ubuntu-on-the-asus-t100ta/ for details
I can confirm that, hust went through it.
But with the t100taf neither grub-efi-ia32 nor grub-efi-amd64 work for me.