in uefi mode can't install grub

[liukai]

in uefi mode can't install grub

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity 2.21.63.6 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.13.0-36.40~16.04.1-generic 4.13.13
Uname: Linux 4.13.0-36-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
CasperVersion: 1.376.2
Date: Sat Sep 15 22:07:00 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed cdrom-detect/try-usb=true noprompt floppy.allowed_drive_mask=0 ignore_uuid boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 16.04.4 LTS "Xenial Xerus" - Release amd64 (20180228)
ProcEnviron:
 LANGUAGE=zh_CN.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=zh_CN.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)