What is this?

On most systems, GRUB shows a message like

GRUB loading.
Welcome to GRUB!

at boot, just before loading the boot menu. Current versions of GRUB do not provide any mechanism to disable this message without patching and recompiling GRUB itself.

This process is cumbersone, as it requires expertise and forces you to recompile / repatch every time you update grub.

grub-shusher contains two tiny .c files that instead of patching the grub source code, they patch the grub binaries or installed master boot record to disable those messages.

The software is generally safe: it looks for a specific set of patterns, and if not all are found, it stops processing. It has been tested on a few machines, and works as expected.

However, I only have access to a handful of machines, and the code will modify your master boot record.

USE IT AT YOUR OWN RISK - YOU ARE RESPONSIBLE FOR BACKING UP AND RESTORING YOUR DATA

At this point, it has been tested on systems with:

• EFI
• GPT
• Standard partition table

If you have success / failure stories to tell, please email me directly (ccontavalli AT gmail.com) or open issues on github (https://github.com/ccontavalli/grub-shusher/issues).

How to use grub-shusher

REPLACE /dev/sda with your GRUB PARTITION, used with grub-setup or grub-install

On Debian Systems with normal partition table (no EFI, no GPT)

# ./setup-debian.sh /dev/sda

... and go read configuring grub.

If you want to setup grub-shusher automatically after each upgrade, you can edit /etc/apt/apt.conf, and add a section like:

DPkg
{
    Post-Invoke {"/opt/projects/grub-shusher/setup-debian.sh /dev/sda >/dev/null 2>/dev/null || true;";};
}

where /opt/projects/grub-shuser is the directory where you downloaded grub-shusher, and /dev/sda is the partition or disk where grub is installed.

On Any Other System (TM) with normal partition table (no EFI, no GPT)

$ make
$ sudo -s
# ./grub-kernel /boot/grub/kernel.img
# ./grub-kernel /usr/lib/grub/i386-pc/kernel.img
# grub-install /dev/sda
# ./mbr /dev/sda

... and done. Note that the order is important:

1. make will compile the code, you need to have GCC installed.
2. grub-kernel ... will remove the 'Welcome to GRUB!' message from the kernel.img file.
3. grub-install /dev/sda will create a new compressed image (by merging several other files, including kernel.img) and install it on your disk.
4. mbr /dev/sda will remove a few other messages from the installed mbr.

... and go read configuring grub.

On Any System (TM) with EFI

$ make
$ sudo -s
# ./grub-kernel /boot/efi/EFI/***/grubx64.efi

... and done. Important:

• make always sure that you have made a backup of grubx64.efi

• replace *** with the distribution name, for example /boot/efi/EFI/manjaro/grubx64.efi.

... and go read configuring grub.

On Any System (TM) with GPT

$ make
$ sudo -s
# ./mbr -g /dev/sda
# ./mbr -g /dev/bios-boot-partition

Note:

• You must provide the -g flag, this is important for GPT partitions.

• You must run mbr twice:

  1. With the partition GRUB was told to use (/dev/sda, in this document).
  2. With the GPT partition, the one marked with the EF02 type. You can find this partition by running something like:

# parted /dev/sda print

Configuring GRUB

To make GRUB entirely quiet, my /etc/defaults/grub has:

GRUB_DEFAULT=0
GRUB_TIMEOUT=0
 
GRUB_HIDDEN_TIMEOUT=5
GRUB_HIDDEN_TIMEOUT_QUIET=true

Note that once you have those lines, you need to run update-grub, and on next reboot, you will have to press 'ESC' or keep 'shift' pressed to get into the grub menu. I suggest you try this before you shush grub.

If something goes wrong, you can:

# apt-get install --reinstall grub2
# grub-install /dev/sda

to clean up after yourself.

You can read more about grub-shusher on this blog post.

Getting back into GRUB

Once you change /etc/defaults/grub and run update-grub, grub will no longer show up at boot. To get into the menu, you can try two things:

• Keep shift pressed during boot. This is the documented mechanism, did not work for me.
• Press ESC at boot. This is a bit tricky, as if you press it too early, most BIOSes will bring you in the BIOS menu. If you press it too late, well, the operating system will have booted already. The rule of thumb is to press it at the time the GRUB menu would have showed up, had it been enabled. If you use the settings above, you have 5 seconds of window to press the button. On my laptopt, this is right after the screen is cleared.

Contributors and THANKS!

Thanks go to:

• Carlo Contavalli, www.github.com/ccontavalli - main author.
• cybnetsurfe3011, www.github.com/cybnetsurfe3011 - GPT support.
• vincent-t, www.github.com/vincent-t - EFI testing and documentation.