My understanding of following config file is that both are identical except for echo lines.
$ cat /boot/grub/grub.cfg
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
set have_grubenv=true
load_env
fi
if [ "${initrdfail}" = 2 ]; then
set initrdfail=
elif [ "${initrdfail}" = 1 ]; then
set next_entry="${prev_entry}"
set prev_entry=
save_env prev_entry
if [ "${next_entry}" ]; then
set initrdfail=2
fi
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="0"
fi
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
else
menuentry_id_option=""
fi
export menuentry_id_option
if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi
function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
}
function initrdfail {
if [ -n "${have_grubenv}" ]; then if [ -n "${partuuid}" ]; then
if [ -z "${initrdfail}" ]; then
set initrdfail=1
if [ -n "${boot_once}" ]; then
set prev_entry="${default}"
save_env prev_entry
fi
fi
save_env initrdfail
fi; fi
}
function recordfail {
set recordfail=1
if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi
}
function load_video {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
}
if [ x$feature_default_font_path = xy ] ; then
font=unicode
else
insmod part_msdos
insmod ext2
set root='hd0,msdos2'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2 bd80955c-2de0-4ff3-bb13-d4340f664fec
else
search --no-floppy --fs-uuid --set=root bd80955c-2de0-4ff3-bb13-d4340f664fec
fi
font="/usr/share/grub/unicode.pf2"
fi
if loadfont $font ; then
set gfxmode=auto
load_video
insmod gfxterm
set locale_dir=$prefix/locale
set lang=en_CA
insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
set timeout=30
else
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=hidden
set timeout=0
# Fallback hidden-timeout code in case the timeout_style feature is
# unavailable.
elif sleep --interruptible 0 ; then
set timeout=0
fi
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
### END /etc/grub.d/05_debian_theme ###
### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
set gfxpayload=""
if [ "" = "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
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-bd80955c-2de0-4ff3-bb13-d4340f664fec' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod ext2
set root='hd0,msdos2'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2 bd80955c-2de0-4ff3-bb13-d4340f664fec
else
search --no-floppy --fs-uuid --set=root bd80955c-2de0-4ff3-bb13-d4340f664fec
fi
linux /boot/vmlinuz-6.2.0-26-generic root=UUID=bd80955c-2de0-4ff3-bb13-d4340f664fec ro quiet splash fsck.repair=no $vt_handoff
initrd /boot/initrd.img-6.2.0-26-generic
}
submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-bd80955c-2de0-4ff3-bb13-d4340f664fec' {
menuentry 'Ubuntu, with Linux 6.2.0-26-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.2.0-26-generic-advanced-bd80955c-2de0-4ff3-bb13-d4340f664fec' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod ext2
set root='hd0,msdos2'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2 bd80955c-2de0-4ff3-bb13-d4340f664fec
else
search --no-floppy --fs-uuid --set=root bd80955c-2de0-4ff3-bb13-d4340f664fec
fi
echo 'Loading Linux 6.2.0-26-generic ...'
linux /boot/vmlinuz-6.2.0-26-generic root=UUID=bd80955c-2de0-4ff3-bb13-d4340f664fec ro quiet splash fsck.repair=no $vt_handoff
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-6.2.0-26-generic
}
menuentry 'Ubuntu, with Linux 6.2.0-26-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.2.0-26-generic-recovery-bd80955c-2de0-4ff3-bb13-d4340f664fec' {
recordfail
load_video
insmod gzio
if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
insmod part_msdos
insmod ext2
set root='hd0,msdos2'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2 bd80955c-2de0-4ff3-bb13-d4340f664fec
else
search --no-floppy --fs-uuid --set=root bd80955c-2de0-4ff3-bb13-d4340f664fec
fi
echo 'Loading Linux 6.2.0-26-generic ...'
linux /boot/vmlinuz-6.2.0-26-generic root=UUID=bd80955c-2de0-4ff3-bb13-d4340f664fec ro recovery nomodeset dis_ucode_ldr
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-6.2.0-26-generic
}
}
### END /etc/grub.d/10_linux ###
### 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/20_memtest86+ ###
### END /etc/grub.d/20_memtest86+ ###
### 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 ###
Perhaps this is related to https://askubuntu.com/questions/1512030/how-to-remove-error-failure-writing-sector-to-hd0-warning-when-booting-ubun or https://askubuntu.com/questions/1511802/ubuntu-22-04-3-black-screen-after-grub-selection-on-read-only-flash-drive, puzzled!
