Talk:GRUB/Tips and tricks

Password protection of non local system boot options

Added this note, which was deleted as it won't survive package upgrades:

To have this applied automatically with grub-mkconfig add --unrestricted to the following lines:

/etc/grub.d/10_linux

[...]
echo "menuentry '$(echo "$title" | grub_quote)' --unrestricted ${CLASS} \$menuentry_id_option 'gnulinux-$version-$type-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
else
echo "menuentry '$(echo "$os" | grub_quote)' --unrestricted ${CLASS} \$menuentry_id_option 'gnulinux-simple-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
[...]

Any suggestions on how to make that work? I.e. is it best to write a custom hook? Lahwaacz?

—This unsigned comment is by Drew33 (talk) 16:09, 8 August 2017‎. Please sign your posts with ~~~~!

I have no idea... -- Lahwaacz (talk) 16:14, 8 August 2017 (UTC)

I'm using this successfully:

/etc/pacman.d/hooks/grub.hook

[Trigger]
Operation = Install
Operation = Upgrade
Type = Package
Target = grub
[Action]
Description = Unrestricting GRUB's linux boot entries...
Depends = sed
When = PostTransaction
Exec = /usr/bin/sed -i -e 's/--class os/--class os --unrestricted/g' /etc/grub.d/10_linux

After this hook is added reinstall GRUB and regenerate grub.cfg:

# pacman -S grub
# grub-mkconfig -o /boot/grub/grub.cfg

Slimmer (talk) 08:02, 3 July 2019 (UTC)

I am now using this custom entry in /etc/grub.d. This works by altering the menuentry_id_option variable that is used for every OS menuentry.

/etc/grub.d/09_make_OS_entries_unrestricted

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

menuentry_id_option="--unrestricted $menuentry_id_option"

Beckab (talk) 14:54, 12 August 2019 (UTC)

Play a tune

I was writing the first part of Pictures at an exhibition by Mussorgsky: Promenade, but i didn't finish it.. :

these are up to number 2 on the score, i think.. (it's trumpets 1,2 as seen on imslp.org, tempo was set arbitrarily at 130 ) Tsester (talk) 08:03, 13 February 2016 (UTC)

GRUB_INIT_TUNE="260 \
392 2 349 2 466 2 523 1 698 1 588 2 524 1 698 1 588 2 466 2 524 2 392 2 349 2 0 2 \
392 2 349 2 466 2 523 1 698 1 588 2 524 1 698 1 588 2 466 2 524 2 392 2 349 2 0 2 \
349 2 392 2 294 2 349 1 392 1 262 2 392 1 440 1 349 2 698 2 588 2 524 1 466 1 349 2 0 2 \
349 2 392 2 294 2 349 1 392 1 311 2 466 1 524 1 415 2 830 2 698 2 622 1 554 1 415 2"

Hiding Boot Menu except on keypress contains hardcoded 3s timeout

I had one heck of a time hunting down a mysterious 3 second timeout that wouldn't go away after I set up (and forgot) the "hide boot menu" trick that creates the file 31_hold_shift.

31_hold_shift contains a code block

 if keystatus; then
   if keystatus --shift; then
     set timeout=-1
   else
     set timeout=0
   fi
 else
   if sleep$verbose --interruptible 3 ; then
     set timeout=0
   fi
 fi

This effectively hardcodes a 3 second timeout, regardless of the TIMEOUT setting in /etc/default/grub, unless a key is pressed on bootup. I modified it to

 if keystatus; then
   if keystatus --shift; then
     set timeout=-1
   else
     set timeout=0
   fi
 fi

Now it does what I want, a $TIMEOUT second timeout unless shift or another key is pressed. I shall leave this page here a bit and replace the gist for the script unless there is disagreement.

Cmc (talk) 20:34, 13 January 2020 (UTC)

UEFI further reading/Alternative install method

A possible reason to put everything into efi-tirectory is dual booting a fully encrypted system with dual-boot, allowing you to directly boot windows without entering the password and unlocking the config-files first Thomasf (talk) 19:14, 12 January 2022 (UTC)

I’m reinstalling GRUB fully onto ESP right now because I did some partition stuff, /boot’s partition number changed, and now GRUB drops to a rescue prompt because it can’t find its modules. If I can just put all GRUB’s modules next to GRUB, then this failure mode can never happen. I don’t see any cons unless you have a small filled-up ESP you can’t grow… —Edit for anyone who comes across this: the new /esp/grub on this x64 system is 5.8 MB.Unawarez (talk) 23:40, 14 July 2024 (UTC)