grub error: can't find command 'gfxmode'.

[watchpocket]

I've made a customized grub menu by placing all entries in the file /etc/grub.d/06_custom.

The grub menu now appears exactly as I want it, *IF* turn off the executable bit for both of the 10_linux and 30_os-prober files.

But when I turn off the 10_linux file (to get rid of menu-entries I don't want), I get:

"error: can't find command 'gfxmode' Press any key to continue..." when I boot the top entry.

If I turn 10_linux back on, I don't get the error message, but a few extraneous menu-entries, that i don't want, appear in the grub menu.

Do I need to copy some of the code from 10_linux into 06_custom?

What might be causing the error?



1 #
2 # If you change this file, run 'sudo update-grub' afterwards to update /boot/grub/grub.cfg.
3 # For full documentation of the options in this file, see:
4 # info -f grub -n 'Simple configuration'
5
6 GRUB_DEFAULT="0"
7 GRUB_TIMEOUT_STYLE="menu"
8 GRUB_TIMEOUT="10"
9 GRUB_RECORDFAIL_TIMEOUT="10"
10 GRUB_DISTRIBUTOR="`lsb_release -i -s 2> /dev/null || echo Debian`"
11 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
12 GRUB_CMDLINE_LINUX=""
13 GRUB_BACKGROUND="/home/rj/Pictures/do_not_move/pic-4-grub.jpg"
14
15 # The resolution used on graphical terminal.
16 # Note that you can use only modes which your graphic card supports via VBE.
17 # You can see them in real GRUB with the command `vbeinfo' or 'videoinfo'.
18 GRUB_GFXMODE="2560x1600x32,1920x1080x32,auto"
19
20 # For a more readable font on high dpi screens, generated with:
21 # sudo grub-mkfont --output=/boot/grub/fonts/DejaVuSansMono40.pf2 --size=40 /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf
22 # per <https://blog.wxm.be/2014/08/29/increase-font-in-grub-for-high-dpi.html>
23 GRUB_FONT="/boot/grub/fonts/DejaVuSansMono40.pf2"
24
25 # The OS_prober feature is disabled by default in GRUB 2.06, which is the version included in
26 # Ubuntu 22.04. This is an upstream change designed to counter potential security issues with
27 # the OS-detecting feature (it mounts partitions to check for other OSes, this could be taken
28 # advantage of, etc). See:
29 # <https://www.omgubuntu.co.uk/2021/12/grub-doesnt-detect-windows-linux-distros-fix>
30 GRUB_DISABLE_OS_PROBER="false"
(The rest of the file is commented-out, but I don't think the settings in this file have much to do with the problem.)

[#&thj^%]

Try with "GRUB_GFXMODE=auto" only, providing that's the file in question
Dang forgot this one as well

# Uncomment to allow the kernel use the same resolution used by grub
GRUB_GFXPAYLOAD_LINUX=keep
and to be clear:

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `videoinfo'
GRUB_GFXMODE=auto

[watchpocket]

Thanks for the suggestion but this didn't get rid of the error message.
There must be something in the 10_linux file about gfxmode that I need to put in 06_custom.

[MAFoElffen]

LMFAO!!!

This is why:


mafoelffen@Mikes-B460M:~$ grep 'function gfxmode' /etc/grub.d/10_linux
function gfxmode {

The function for 'gfxmode' is defined in /etc/grub.d/10_linux. You disabled the execution bit on that script, so GRUB_GFXMODE is not defined. Make that script executable again and that error will go away...

Quote: "It's okay. I saw this work once in a cartoon..."

[watchpocket]

No, I get unwanted entries in the grub menu when I make 10_linux executable, as stated in my original post.

[MAFoElffen]

Not sure what entries you want to hide... For me, to skip something, I edit /etc/default/grub and add the line:


GRUB_OS_PROBER_SKIP_LIST="<UUID><PATH-TO-EFI_FILE>"

in my case that would be


GRUB_OS_PROBER_SKIP_LIST="0150-726C@/efi/Microsoft/Boot/bootmgfw.efi"


*** But looking at and tracing through the code in /etc/grub.d/10_linux, I suspect if you uncomment this line in your /etc/default/grub file


#GRUB_DISABLE_RECOVERY="true"

Add this line


GRUB_DISABLE_SUBMENU="true"

and change line #408 in file /etc/grub.d/10_linux from this


is_top_level=true

To this


is_top_level=false

That it will stop creating any menuentries from that script. That would toggle all the if statements that create menuentries to false.

EDIT-- And still have the logic there to write the gfxmode define interactively to grub.cfg...

[watchpocket]

Not sure what entries you want to hide...

I want to hide the two default entries that say "Ubuntu" and "Advanced Options for Ubuntu".

Those are the only two default menu-entries left that display if I leave executable ON for 10_linux, and with the executable OFF for 30_os-prober.

(To recap: if I turn OFF executable for both the 10_linux and 30_os-prober scripts, my menu is exactly as I want it, but that's when I get the "can't find command gfxmode" error.)

I have made all the menu entries I want in /etc/grub.d/06_custom.


For me, to skip something, I edit /etc/default/grub and add the line:


GRUB_OS_PROBER_SKIP_LIST="<UUID><PATH-TO-EFI_FILE>"

in my case that would be

in the terminal when I ran sudo update-grub
GRUB_OS_PROBER_SKIP_LIST="0150-726C@/efi/Microsoft/Boot/bootmgfw.efi"


Where do I find the UUID and path-to-efi-file for those two default menu entries? (Likely somewhere in /etc/grub.d/10_linux, but where?)

I made all your suggestions below, ran sudo update grub, and got the same 'unable to find command gfxmode' error message in grub when I selected to boot the top menu entry. (This of course is with 10_linux executable ON.)

But in addition I got an error message in the terminal when I ran sudo update-grub -- about line 451 of the .cfg file. I could find nothing wrong with that line in 10_linux (but then I don't know what to look for):


451 initrd="${initrd_early} ${initrd_real}"

None of the below worked, but thank you for the suggestions.

*** But looking at and tracing through the code in /etc/grub.d/10_linux, I suspect if you uncomment this line in your /etc/default/grub file


#GRUB_DISABLE_RECOVERY="true"

Add this line


GRUB_DISABLE_SUBMENU="true"

and change line #408 in file /etc/grub.d/10_linux from this


is_top_level=true

To this


is_top_level=false

That it will stop creating any menuentries from that script. That would toggle all the if statements that create menuentries to false.

EDIT-- And still have the logic there to write the gfxmode define interactively to grub.cfg...

[MAFoElffen]

Variable GRUB_OS_PROBER_SKIP_LIST only works to skip entries found by script 30_os-prober... Which I now understand, that you manually turned off via the execution bit, instead of toggling off with GRUB_OS_PROBER_DISABLE...

FYI, just to answer your question about that... It won't help you with what you are trying to do, but you asked. Find the "Path" in output from 'efibootmgr -v' looking through the output of the EFI boot entry, and find the UUID from 'blkid' for the specific EFI directory. But that is not what you are doing, so will not help you to skip over and not create those two entries.


mafoelffen@Mikes-B460M:~$ sudo efibootmgr -v
BootCurrent: 0002
Timeout: 1 seconds
BootOrder: 0002,0000
Boot0000* Windows Boot Manager HD(1,GPT,e72b3745-510c-481f-95f6-f721bc03e49e,0x800,0x100000)/File(\EFI\MICROSOFT\BOOT\BOOTMGFW.EFI)WINDOWS..... ....x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}...d................
Boot0002* ubuntu HD(1,GPT,e72b3745-510c-481f-95f6-f721bc03e49e,0x800,0x100000)/File(\EFI\UBUNTU\SHIMX64.EFI)
mafoelffen@Mikes-B460M:~$ sudo blkid | grep -e 'e72b3745-510c-481f-95f6-f721bc03e49e'
/dev/nvme4n1p1: UUID="0150-726C" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="e72b3745-510c-481f-95f6-f721bc03e49e"

Using


GRUB_DISABLE_SUBMENU="true'

Should turn off any submenus, which the Advanced Menu is a submenu. On the default top level menu's... Hmmmm.

I don't know yet "for sure". I am thinking of spinning up a VM and check into this for myself. I am now curious. I just have to update the packages in my PPA for the system-info script and mow the lawn first... LOL.

[watchpocket]

With all the scripts in /etc/grub.d/ set as executable, I do not get the error message mentioned above when I select to boot a menu item.

I DO get the two unwanted bottom menu entries (see attached pic) of "Ubuntu" and "Advanced options for Ubuntu".

In /etc/default/grub I have:

GRUB_DISABLE_OS_PROBER="true" and

(commented-out):
#GRUB_DISABLE_RECOVERY="true"
#GRUB_DISABLE_SUBMENU="true"

https://ubuntuforums.org/attachment.php?attachmentid=292289&stc=1


(I want to keep the very bottom "UEFI Firmware settings" entry. That's in my 06_custom script.)

If I make script 10_linux UN-executable, I get rid of the 2 unwanted menu entries, but then I get the error message.

[oldfred]

The rule is not to update grub.cfg but run sudo update-grub to create it. That uses the scripts & grub configuration settings.
But it sounds like you are the exception to the rule.

I have just installed grub to a flash drive with no install & manually created my own grub.cfg.

You can turn off all scripts & create your own grub.cfg that is just a copy of your 06_custom and maybe some of the settings from /etc/default/grub included. How does your grub.cfg differ from your 06_custom?

[MAFoElffen]

@oldfred --
That's what I was thinking about... If he generated the grub.cfg file, then edited it to remove all the unwanted menu entries...

Then set the file to read-only:


chmod 0444 /boot/grub/grub.cfg

Then it would protect it from getting 'updated' / changed. Keeping another copy of it, for the just in cases... That way it would have all the defines for gfxmode and such inside it.

Just trying to think of things. That's what we used to do before that file was dynamically written.And when resolv.conf got changed to dynamic, and needed a helper...

[oldfred]

You also can just change all the scripts to be not executable. Not sure if then any issue when it tries to run update or not.

[watchpocket]

How does your grub.cfg differ from your 06_custom?

06_custom contains:

(a) the menu-entry code for the first six menu (and submenu) items that are in the pic above;
(b) the 41_custom script because I have a small custom.cfg file that provides the colors for the grub menu.

That's all that is in 06_custom.

-------------------------------------------------------

the /boot/grub/grub.cfg file contains much more:

(a) a ### BEGIN /etc/grub.d/00_header ### section;
(b) a ### BEGIN /etc/grub.d/05_debian_theme ### section;
(c) a ### BEGIN /etc/grub.d/06_custom ### section (which is a copy of my entire 06_custom);
(d) a ### BEGIN /etc/grub.d/10_linux ### section;

and below all that is this:


### BEGIN /etc/grub.d/10_linux_zfs ###
### END /etc/grub.d/10_linux_zfs ###

### BEGIN /etc/grub.d/20_linux_xen ###

### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
*.......fwsetup
}
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/35_fwupd ###
### END /etc/grub.d/35_fwupd ###

### BEGIN /etc/grub.d/40_custom ###
# 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.
#
#
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f ${config_directory}/custom.cfg ]; then
source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###

[watchpocket]

You also can just change all the scripts to be not executable. Not sure if then any issue when it tries to run update or not.

Just did that with executable off for all scripts higher that 06_custom, and at the moment, that causes the same error message to appear when I select to boot the top (main) menu item (because that happens when I make the "10_linux" script unexecutable);

and it also caused the bottom menu item "UEFI Firmware Settings" to not appear, because I made the "30_uefi_firmware" script unexecutable.


Apart from getting the menu right with no error message, this page:
<https://help.ubuntu.com/community/Grub2/CustomMenus#Removing_Default_Script_Entries>

describes how to be able to always boot the current kernel:

There is a potential drawback of a custom menu when the 10_linux and/or 30_os-prober scripts have been disabled. A copied Linux menuentry normally contains a specific kernel and initrd image version number (such as 3.2.0-24) and will not change if a new kernel is introduced.

If the user wishes to always boot the current kernel, the linux and initrd lines of the can take advantage of the symlinks placed in /. These links always point to the most recent kernel. If they are referenced in the menuentry and the symlinks exist, the menuentry will always point to the latest kernel.

Replace the normal linux and initrd references, which normally contain the complete kernel version, with the following:



linux /vmlinuz root=UUID=dbd69ed2-530c-4409-8f5a-a3f1ea41fc67 ro quiet splash $vt_handoff{


initrd /initrd.img




I believe in my case that would be:
/boot/initrd.img -->
and /boot/vmlinuz -->

I think those are the symlinks he's talking about. What I don't understand is what UUID to put there.

[oldfred]

Some examples of custom grub.
How to: Create a Customized GRUB2 Screen that is Maintenance Free.- Cavsfan
https://help.ubuntu.com/community/MaintenanceFreeCustomGrub2Screen
https://www.gnu.org/software/grub/manual/grub/grub.html#Multi_002dboot-manual-config
https://help.ubuntu.com/community/Grub2/CustomMenus
http://ubuntuforums.org/showthread.php?t=2076205
Configfile example to another grub.cfg
This is a very long mega-thread. You may want to read beginning or first page, then jump to end & work backwards for latest posts and most current info.
https://ubuntuforums.org/showthread.php?t=2076205&p=13787835#post13787835

[watchpocket]

So the original problem was that whenever I turned off executable for the /etc/grub.d/10_linux script, I would always get the error message:

error: can't find command 'gfxmode' whenever I selected to boot my top main grub menu entry.

And the reason I wanted the 10_linux script turned off is that if I left it on, I got two unwanted menu items in my grub menu: "Ubuntu" and "Advanced options for Ubuntu", when I already had all the menu items I wanted in my own 06_custom script (except for the bottom menu item "UEFI Firmware Settings" which is provided by the /etc/grub.d/30_uefi_firmware script).

First I tried (and failed) to make the /boot/grub/grub.cfg file writeable and tried to edit it (which you cannot do, because after you do a sudo update-grub, the grub.cfg file deletes all your changes and goes back to being read-only).

But in the process of trying to do that (and looking through grub.cfg), I noticed this bit of code -- which is actually from the 10_linux script (though it looks different there) -- and immediately recognized it as what I needed to stop the error message:

### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
set gfxpayload="${1}"
if [ "${1}" = "keep" ]; then
set vt_handoff=vt.handoff=7
else
set vt_handoff=
fi
}
if [ "${recordfail}" != 1 ]; then
if [ -e ${prefix}/gfxblacklist.txt ]; then
if [ ${grub_platform} != pc ]; then
set linux_gfx_mode=keep
elif hwmatch ${prefix}/gfxblacklist.txt 3; then
if [ ${match} = 0 ]; then
set linux_gfx_mode=keep
else
set linux_gfx_mode=text
fi
else
set linux_gfx_mode=text
fi
else
set linux_gfx_mode=keep
fi
else
set linux_gfx_mode=text
fi
export linux_gfx_mode

So I copied this block of code from grub.cfg and put it at the top of my 06_custom script and presto, the error message was gone when I booted an entry. There may well be different ways to solve the problem, but this is how i did it, and it appears to have worked. Thanks for the tips & suggestions.