I tried your suggestion Simon, but it did not help
I then uninstalled and re-installed 'shim-signed' but the error still remains:
####
Setting up shim-signed (1.5~12.04.2+0.4-0ubuntu4) ...
install_device not specified.
Usage: grub-install [OPTION] install_device
Install GRUB on your drive.
####
I tried your suggestion Simon, but it did not help
I then uninstalled and re-installed 'shim-signed' but the error still remains:
#### 04.2+0. 4-0ubuntu4) ...
Setting up shim-signed (1.5~12.
install_device not specified.
Usage: grub-install [OPTION] install_device
Install GRUB on your drive.
####