Grub efi amd64 signed package failed

Dear sir,
When i install ubuntu 16.04,show error message "Grub-efi-amd64-signed package-failed to install into /target/.Without the GRUB boot loader , the installed system will not boot.
And i boot usb live and install bootrepair and type followed command

sudo chroot "/mnt/boot-sav/sda6" dpkg --configure -a
sudo chroot "/mnt/boot-sav/sda6" apt-get install -fy
sudo chroot "/mnt/boot-sav/sda6" apt-get purge -y --force-yes grub*-common grub-common:i386 shim-signed linux-signed*

but show following error
shin-signed
grub-efi-amd64 signed error