package grub-efi-amd64-signed 1.66+2.02~beta2-36ubuntu3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1 after upgrade from 140.4 to 16.04

[mattip]

I upgraded my system, an ASUS laptop dual boot w/win8, which needs EUFI signed booting AFAIK

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: grub-efi-amd64-signed 1.66+2.02~beta2-36ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-24.43-generic 4.4.10
Uname: Linux 4.4.0-24-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
Date: Fri Jun 24 15:37:32 2016
DuplicateSignature:
 package:grub-efi-amd64-signed:1.66+2.02~beta2-36ubuntu3
 Installing for x86_64-efi platform.
 grub-install: error: cannot find EFI directory.
 dpkg: error processing package grub-efi-amd64-signed (--configure):
  subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2014-11-13 (589 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.12~ubuntu16.04.1
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed 1.66+2.02~beta2-36ubuntu3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2016-06-24 (0 days ago)