Bug#721048: grub-common: Update of EFI version of grub fails when EFI partition is not mounted

[Debian Bugreporter]

Package: grub-common

Version: 2.00-18
Severity: normal

Dear Maintainer,

I tried to upgrade the EFI version of grub installed in
my system using the following command:

$ sudo /usr/sbin/grub-install /dev/sdaX

(where sdaX is the partition where my root filesystem and grub
is installed).

My uprgade attempt wasn't completely successful since on reboot
I was brought to the grub rescue console.

On investigation I found that the problem arose because my EFI
partition wasn't mounted. To avoid polluting my system, I had
made a separate 1 MB EFI partition that I normally don't
mount. I managed to successfully update my EFI grub
installation using the following sequence of commands:

$ sudo mount /dev/sdaY /boot/efi
$ sudo /usr/sbin/grub-install /dev/sdaX

(where sdaY is my small EFI partition, and sdaX is my / partition).

This is necessary because grub needs to update the following file:

/boot/efi/EFI/debian/grubx64.efi

(which is not possible if the EFI partition isn't mounted).

I'm marking this bug report with normal severity since my setup is most
likely a corner case, and most users would probably have their EFI partition
permanently mounted (less secure but more convenient).

However, I do believe that grub-install should either (1) be fixed to
force or allow the mounting of the EFI partition or (2) at least
notify or WARN the user that the EFI version of grub requires the
EFI parition to be mounted first. A third alternative is to
(3) make grub-install fail if a VFAT filesystem is NOT mounted at
/boot/efi (inasmuch as EFI is broken in its ability to boot native
Linux filesystems).

-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (900, 'testing'), (90, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.10-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_SG.UTF-8, LC_CTYPE=en_SG.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages grub-common depends on:
ii  gettext-base        0.18.3.1-1
ii  libc6               2.17-92
ii  libdevmapper1.02.1  2:1.02.77-5
ii  libfreetype6        2.4.9-1.1
ii  libfuse2            2.9.2-4
ii  liblzma5            5.1.1alpha+20120614-2
ii  zlib1g              1:1.2.8.dfsg-1

Versions of packages grub-common recommends:
ii  os-prober  1.63

Versions of packages grub-common suggests:
ii  console-setup  1.95
ii  desktop-base   7.0.3
pn  grub-emu       <none>
pn  multiboot-doc  <none>
ii  xorriso        1.2.2-2

-- no debconf information