(Ubuntu 16.04.1, non-UEFI) package shim-signed 1.18~16.04.1+0.8-0ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

grub failed to load

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: shim-signed 1.18~16.04.1+0.8-0ubuntu2
ProcVersionSignature: Ubuntu 4.4.0-47.68-generic 4.4.24
Uname: Linux 4.4.0-47-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
BootEFIContents:
 fw
 fwupx64.efi
Date: Thu Nov 10 18:54:02 2016
Df:
 Filesystem 1K-blocks Used Available Use% Mounted on
 /dev/sda3 479807248 37154320 418280144 9% /
 /dev/sdb 1477840 1477840 0 100% /cdrom
 udev 1964868 0 1964868 0% /dev
 tmpfs 395900 11224 384676 3% /run
EFIBootMgr: Error: command ['efibootmgr', '-v'] failed with exit code 2: efibootmgr: EFI variables are not supported on this system.
ErrorMessage: subprocess installed post-installation script returned error exit status 1
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.12~ubuntu16.04.1
SourcePackage: shim-signed
Title: package shim-signed 1.18~16.04.1+0.8-0ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)