# How to prevent changes of GRUB\_ENABLE\_BLSCFG in /etc/default/grub

**URL:** <https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505>\
**Category:** Rocky Linux Help & Support\
**Tags:** rocky-linux-8\
**Created:** [May 20, 2025, 1:56pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505 "2025-05-20T13:56:16Z")\
**Posts on this page:** 13\
**Page:** 1

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 20, 2025, 1:56pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/1 "2025-05-20T13:56:16Z")

</div>

With Rocky Linux 8.10 in /etc/default/grub I have GRUB\_ENABLE\_BLSCFG=false

GRUB\_TIMEOUT=5  
GRUB\_DISTRIBUTOR=“$(sed ‘s, release .\*$,g’ /etc/system-release)”  
GRUB\_DEFAULT=saved  
GRUB\_DISABLE\_SUBMENU=true  
GRUB\_CMDLINE\_LINUX=“console=tty0 console=ttyS0,115200n8 resume=/dev/mapper/VolGroup-swapvol rd.lvm.lv=VolGroup/rootvol rd.lvm.lv=VolGroup/swapvol rhgb quiet earlyprintk=ttyS0 net.ifnames=0 ipv6.disable=1”  
GRUB\_DISABLE\_RECOVERY=“true”  
**GRUB\_ENABLE\_BLSCFG=true**  
GRUB\_TERMINAL=“console serial”  
GRUB\_SERIAL\_COMMAND=“serial --speed=115200”

A “dnf update” that included grub2-tools changed it back to GRUB\_ENABLE\_BLSCFG=true

Is there some way to prevent this from happening in future grub2-tools updates? Note that the update didn’t change other entries back to their default values. For example, it kept my GRUB\_TIMEOUT=20

Thanks!

---

<div class="post-metadata">

**Author:** ![iwalker](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/iwalker/32/2599_2.png) [@iwalker](https://forums.rockylinux.org/u/iwalker)\
**Post date:** [May 20, 2025, 3:14pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/2 "2025-05-20T15:14:40Z")

</div>

For what reason are you setting it to false for? I so no reason to do this. Maybe explain why you need it to be false?

---

<div class="post-metadata">

**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\
**Post date:** [May 20, 2025, 7:39pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/3 "2025-05-20T19:39:10Z")

</div>

Apart from that, AFAIK, a package update may _replace_ a file, but not _modify_.

Although, a package may have _scripts_ that do.  
Does `rpm -q --scripts grub2-tools` show something that would edit the `/etc/default/grub`?

---

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 21, 2025, 8:12am UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/4 "2025-05-21T08:12:57Z")

</div>

I need to set it to true to make the serial console work on AWS:

I opened the case 174660975500706, following the AWS instructions I was able to enable the serial console for the released VWs

On redhat 8 I don’t have this problem. The value remains “true” even after the update.

I would expect the same behavior with rocky8 too

---

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 21, 2025, 8:23am UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/5 "2025-05-21T08:23:49Z")

</div>

Hi,  
If it can be useful, I noticed some big differences between redhat8 and rocky8 regarding this file: /etc/grub.d/10\_linux  
in this file is written the management of the parameter “GRUB\_ENABLE\_BLSCFG” that is overwritten during update

---

<div class="post-metadata">

**Author:** ![nouvo09](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/nouvo09/32/2920_2.png) [@nouvo09](https://forums.rockylinux.org/u/nouvo09)\
**Post date:** [May 21, 2025, 12:37pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/6 "2025-05-21T12:37:31Z")

</div>

On my Rocky9, I set it to false at install time, monthes ago and none of the updates did change anything

---

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 21, 2025, 12:48pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/7 "2025-05-21T12:48:50Z")

</div>

on rockylinux 9 i have no problems either.

the problem is only on rockylinux 8

---

<div class="post-metadata">

**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\
**Post date:** [May 21, 2025, 1:53pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/8 "2025-05-21T13:53:32Z")

</div>

> [@Vittory003](#):
>
> `/etc/grub.d/10_linux`  
> in this file is written the management of the parameter “GRUB\_ENABLE\_BLSCFG”

I don’t have rhel8 nor rocky8. Can you show the part you refer to and how they differ?

---

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 21, 2025, 2:21pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/9 "2025-05-21T14:21:34Z")

</div>

below are the 2 configuration files

**this is 10\_linux in redhat 8**

````auto
#! /bin/sh
set -e

# grub-mkconfig helper script.
# Copyright (C) 2006,2007,2008,2009,2010 Free Software Foundation, Inc.
#
# GRUB is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GRUB is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GRUB. If not, see <http://www.gnu.org/licenses/>.

prefix="/usr"
exec_prefix="/usr"
datarootdir="/usr/share"

. "$pkgdatadir/grub-mkconfig_lib"

export TEXTDOMAIN=grub
export TEXTDOMAINDIR="${datarootdir}/locale"

CLASS="--class gnu-linux --class gnu --class os --unrestricted"

if ["x${GRUB_DISTRIBUTOR}" = "x"] ; then
  OS="$(eval $(grep PRETTY_NAME /etc/os-release) ; echo ${PRETTY_NAME})"
  CLASS="--class $(eval $(grep '^ID_LIKE=\|^ID=' /etc/os-release) ; [-n "${ID_LIKE}"] && echo ${ID_LIKE} || echo ${ID}) ${CLASS}"
else
  OS="${GRUB_DISTRIBUTOR}"
  CLASS="--class $(echo ${GRUB_DISTRIBUTOR} | tr 'A-Z' 'a-z' | cut -d' ' -f1|LC_ALL=C sed 's,[^[:alnum:]_],_,g') ${CLASS}"
fi

# loop-AES arranges things so that /dev/loop/X can be our root device, but
# the initrds that Linux uses don't like that.
case ${GRUB_DEVICE} in
  /dev/loop/*|/dev/loop[0-9])
    GRUB_DEVICE=losetup ${GRUB_DEVICE} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"
  ;;
esac

# Default to disabling partition uuid support to maintian compatibility with
# older kernels.
GRUB_DISABLE_LINUX_PARTUUID=${GRUB_DISABLE_LINUX_PARTUUID-true}

# btrfs may reside on multiple devices. We cannot pass them as value of root= parameter
# and mounting btrfs requires user space scanning, so force UUID in this case.
if ( ["x${GRUB_DEVICE_UUID}" = "x"] && ["x${GRUB_DEVICE_PARTUUID}" = "x"] ) \
    || ( ["x${GRUB_DISABLE_LINUX_UUID}" = "xtrue"] \
        && ["x${GRUB_DISABLE_LINUX_PARTUUID}" = "xtrue"] ) \
    || ( ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
        && ! test -e "/dev/disk/by-partuuid/${GRUB_DEVICE_PARTUUID}" ) \
    || ( test -e "${GRUB_DEVICE}" && uses_abstraction "${GRUB_DEVICE}" lvm ); then
  LINUX_ROOT_DEVICE=${GRUB_DEVICE}
elif ["x${GRUB_DEVICE_UUID}" = "x"] \
    || ["x${GRUB_DISABLE_LINUX_UUID}" = "xtrue"]; then
  LINUX_ROOT_DEVICE=PARTUUID=${GRUB_DEVICE_PARTUUID}
else
  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
fi

case x"$GRUB_FS" in
    xbtrfs)
        if ["x${SUSE_BTRFS_SNAPSHOT_BOOTING}" = "xtrue"]; then
        GRUB_CMDLINE_LINUX="${GRUB_CMDLINE_LINUX} \${extra_cmdline}"
        else
        rootsubvol="make_system_path_relative_to_its_root /"
        rootsubvol="${rootsubvol#/}"
        if ["x${rootsubvol}" != x]; then
            GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
        fi
        fi;;
    xzfs)
        rpool=${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || true
        bootfs="make_system_path_relative_to_its_root / | sed -e "s,@$,,""
        LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs}"
        ;;
esac

populate_header_warn()
{
cat <<EOF

# This section was generated by a script. Do not modify the generated file - all changes
# will be lost the next time file is regenerated. Instead edit the BootLoaderSpec files.
#
# The blscfg command parses the BootLoaderSpec files stored in /boot/loader/entries and
# populates the boot menu. Please refer to the Boot Loader Specification documentation
# for the files format: https://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/.

EOF
}

mktitle ()
{
  local title_type
  local version
  local OS_NAME
  local OS_VERS

  title_type=$1 && shift
  version=$1 && shift

  OS_NAME="$(eval $(grep ^NAME= /etc/os-release) ; echo ${NAME})"
  OS_VERS="$(eval $(grep ^VERSION= /etc/os-release) ; echo ${VERSION})"

  case $title_type in
    recovery)
      title=$(printf '%s (%s) %s (recovery mode)' \
                     "${OS_NAME}" "${version}" "${OS_VERS}")
      ;;
    *)
      title=$(printf '%s (%s) %s' \
                     "${OS_NAME}" "${version}" "${OS_VERS}")
      ;;
  esac
  echo -n ${title}
}

title_correction_code=

linux_entry ()
{
  os="$1"
  version="$2"
  type="$3"
  isdebug="$4"
  args="$5"

  if [-z "$boot_device_id"]; then
      boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
  fi

  if ["x${GRUB_ENABLE_BLSCFG}" = "xtrue"]; then
    if [x$dirname = x/]; then
      if [-z "${prepare_root_cache}"]; then
        prepare_grub_to_access_device ${GRUB_DEVICE}
      fi
    else
      if [-z "${prepare_boot_cache}"]; then
        prepare_grub_to_access_device ${GRUB_DEVICE_BOOT}
      fi
    fi

    if [-d /sys/firmware/efi]; then
        bootefi_device="${grub_probe} --target=device /boot/efi/"
        prepare_grub_to_access_device ${bootefi_device} boot
    else
        boot_device="${grub_probe} --target=device /boot/"
        prepare_grub_to_access_device ${boot_device} boot
    fi

    populate_header_warn

    cat << EOF
# The kernelopts variable should be defined in the grubenv file. But to ensure that menu
# entries populated from BootLoaderSpec files that use this variable work correctly even
# without a grubenv file, define a fallback kernelopts variable if this has not been set.
#
# The kernelopts variable in the grubenv file can be modified using the grubby tool or by
# executing the grub2-mkconfig tool. For the latter, the values of the GRUB_CMDLINE_LINUX
# and GRUB_CMDLINE_LINUX_DEFAULT options from /etc/default/grub file are used to set both
# the kernelopts variable in the grubenv file and the fallback kernelopts variable.
if [-z "\${kernelopts}"]; then
  set kernelopts="root=${linux_root_device_thisversion} ro ${args}"
fi

insmod blscfg
blscfg
EOF

    if ["x${GRUB_GRUBENV_UPDATE}" = "xyes"]; then
        ${grub_editenv} - set kernelopts="root=${linux_root_device_thisversion} ro ${args}"
    fi

    exit 0
  fi

  if [x$type != xsimple] ; then
      title=$(mktitle "$type" "$version")
      if [x"$title" = x"$GRUB_ACTUAL_DEFAULT"] || [x"Previous Linux versions>$title" = x"$GRUB_ACTUAL_DEFAULT"]; then
          replacement_title="$(echo "Advanced options for ${OS}" | sed 's,>,>>,g')>$(echo "$title" | sed 's,>,>>,g')"
          quoted="$(echo "$GRUB_ACTUAL_DEFAULT" | grub_quote)"
          title_correction_code="${title_correction_code}if [\"x\$default\" = '$quoted']; then default='$(echo "$replacement_title" | grub_quote)'; fi;"
      fi
      if [x$isdebug = xdebug]; then
          title="$title${GRUB_LINUX_DEBUG_TITLE_POSTFIX}"
      fi
      echo "menuentry '$(echo "$title" | grub_quote)' ${CLASS} \$menuentry_id_option 'gnulinux-$version-$type-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
  else
      echo "menuentry '$(echo "$os" | grub_quote)' ${CLASS} \$menuentry_id_option 'gnulinux-simple-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
  fi
  if [x$type != xrecovery] ; then
      save_default_entry | grub_add_tab
  fi

  # Use ELILO's generic "efifb" when it's known to be available.
  # FIXME: We need an interface to select vesafb in case efifb can't be used.
  if ["x$GRUB_GFXPAYLOAD_LINUX" = x]; then
      echo " load_video" | sed "s/^/$submenu_indentation/"
      if grep -qx "CONFIG_FB_EFI=y" "${config}" 2> /dev/null \
          && grep -qx "CONFIG_VT_HW_CONSOLE_BINDING=y" "${config}" 2> /dev/null; then
          echo " set gfxpayload=keep" | sed "s/^/$submenu_indentation/"
      fi
  else
      if ["x$GRUB_GFXPAYLOAD_LINUX" != xtext]; then
          echo " load_video" | sed "s/^/$submenu_indentation/"
      fi
      echo " set gfxpayload=$GRUB_GFXPAYLOAD_LINUX" | sed "s/^/$submenu_indentation/"
  fi

  echo " insmod gzio" | sed "s/^/$submenu_indentation/"

  if [x$dirname = x/]; then
    if [-z "${prepare_root_cache}"]; then
      prepare_root_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE} | grub_add_tab)"
    fi
    printf '%s\n' "${prepare_root_cache}" | sed "s/^/$submenu_indentation/"
  else
    if [-z "${prepare_boot_cache}"]; then
      prepare_boot_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE_BOOT} | grub_add_tab)"
    fi
    printf '%s\n' "${prepare_boot_cache}" | sed "s/^/$submenu_indentation/"
  fi
  sed "s/^/$submenu_indentation/" << EOF
        linux ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}
EOF
  if test -n "${initrd}" ; then
    initrd_path=
    for i in ${initrd}; do
      initrd_path="${initrd_path} ${rel_dirname}/${i}"
    done
    sed "s/^/$submenu_indentation/" << EOF
        initrd $(echo $initrd_path)
EOF
  fi
  if test -n "${fdt}" ; then
    sed "s/^/$submenu_indentation/" << EOF
        devicetree ${rel_dirname}/${fdt}
EOF
  fi
  sed "s/^/$submenu_indentation/" << EOF
}
EOF
}

machine=uname -m
case "x$machine" in
    xi?86 | xx86_64)
        list=
        for i in /boot/vmlinuz-* /vmlinuz-* /boot/kernel-* ; do
            if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
        done ;;
    *)
        list=
        for i in /boot/vmlinuz-* /boot/vmlinux-* /vmlinuz-* /vmlinux-* /boot/kernel-* ; do
                  if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
        done ;;
esac

if ["x${GRUB_ENABLE_BLSCFG}" = "xtrue"]; then
    for i in /boot/ostree/*/vmlinuz-* ; do
        if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
    done
fi

case "$machine" in
    i?86) GENKERNEL_ARCH="x86" ;;
    mips|mips64) GENKERNEL_ARCH="mips" ;;
    mipsel|mips64el) GENKERNEL_ARCH="mipsel" ;;
    arm*) GENKERNEL_ARCH="arm" ;;
    *) GENKERNEL_ARCH="$machine" ;;
esac

prepare_boot_cache=
prepare_root_cache=
boot_device_id=
title_correction_code=

# Extra indentation to add to menu entries in a submenu. We're not in a submenu
# yet, so it's empty. In a submenu it will be equal to '\t' (one tab).
submenu_indentation=""

is_top_level=true
while ["x$list" != "x"] ; do
  linux=version_find_latest $list
  if ["x${GRUB_ENABLE_BLSCFG}" != "xtrue"]; then
    gettext_printf "Found linux image: %s\n" "$linux" >&2
  fi

  basename=basename $linux
  dirname=dirname $linux
  rel_dirname=make_system_path_relative_to_its_root $dirname
  version=echo $basename | sed -e "s,^[^0-9]*-,,g"
  alt_version=echo $version | sed -e "s,\.old$,,g"
  linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"

  initrd_early=
  for i in ${GRUB_EARLY_INITRD_LINUX_STOCK} \
           ${GRUB_EARLY_INITRD_LINUX_CUSTOM}; do
    if test -e "${dirname}/${i}" ; then
      initrd_early="${initrd_early} ${i}"
    fi
  done

  initrd_real=
  for i in "initrd.img-${version}" "initrd-${version}.img" "initrd-${version}.gz" \
           "initrd-${version}" "initramfs-${version}.img" \
           "initrd.img-${alt_version}" "initrd-${alt_version}.img" \
           "initrd-${alt_version}" "initramfs-${alt_version}.img" \
           "initramfs-genkernel-${version}" \
           "initramfs-genkernel-${alt_version}" \
           "initramfs-genkernel-${GENKERNEL_ARCH}-${version}" \
           "initramfs-genkernel-${GENKERNEL_ARCH}-${alt_version}"; do
    if test -e "${dirname}/${i}" ; then
      initrd_real="${i}"
      break
    fi
  done

  initrd=
  if test -n "${initrd_early}" || test -n "${initrd_real}"; then
    initrd="${initrd_early} ${initrd_real}"

    initrd_display=
    for i in ${initrd}; do
      initrd_display="${initrd_display} ${dirname}/${i}"
    done
    if ["x${GRUB_ENABLE_BLSCFG}" != "xtrue"]; then
      gettext_printf "Found initrd image: %s\n" "$(echo $initrd_display)" >&2
    fi
  fi

  fdt=
  for i in "dtb-${version}" "dtb-${alt_version}"; do
    if test -f "${dirname}/${i}/${GRUB_DEFAULT_DTB}" ; then
      fdt="${i}/${GRUB_DEFAULT_DTB}"
      break
    fi
  done

  config=
  for i in "${dirname}/config-${version}" "${dirname}/config-${alt_version}" "/etc/kernels/kernel-config-${version}" ; do
    if test -e "${i}" ; then
      config="${i}"
      break
    fi
  done

  initramfs=
  if test -n "${config}" ; then
      initramfs=grep CONFIG_INITRAMFS_SOURCE= "${config}" | cut -f2 -d= | tr -d \"
  fi

  if test -z "${initramfs}" && test -z "${initrd_real}" ; then
    # "UUID=" and "ZFS=" magic is parsed by initrd or initramfs. Since there's
    # no initrd or builtin initramfs, it can't work here.
    if ["x${GRUB_DEVICE_PARTUUID}" = "x"] \
        || ["x${GRUB_DISABLE_LINUX_PARTUUID}" = "xtrue"]; then

        linux_root_device_thisversion=${GRUB_DEVICE}
    else
        linux_root_device_thisversion=PARTUUID=${GRUB_DEVICE_PARTUUID}
    fi
  fi

  if ["x${GRUB_DISABLE_SUBMENU}" = "xyes"] || ["x${GRUB_DISABLE_SUBMENU}" = "xy"]; then
    GRUB_DISABLE_SUBMENU="true"
  fi

  if ["x$is_top_level" = xtrue] && ["x${GRUB_DISABLE_SUBMENU}" != xtrue]; then
    linux_entry "${OS}" "${version}" simple standard \
    "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
    if ["x$GRUB_LINUX_MAKE_DEBUG" = "xtrue"]; then
      linux_entry "${OS}" "${version}" simple debug \
        "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} ${GRUB_CMDLINE_LINUX_DEBUG}"
    fi

    submenu_indentation="$grub_tab"

    if [-z "$boot_device_id"]; then
        boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
    fi
    # TRANSLATORS: %s is replaced with an OS name
    echo "submenu '$(gettext_printf "Advanced options for %s" "${OS}" | grub_quote)' \$menuentry_id_option 'gnulinux-advanced-$boot_device_id' {"
    is_top_level=false
  fi

  linux_entry "${OS}" "${version}" advanced standard \
              "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
  if ["x$GRUB_LINUX_MAKE_DEBUG" = "xtrue"]; then
    linux_entry "${OS}" "${version}" advanced debug \
                "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} ${GRUB_CMDLINE_LINUX_DEBUG}"
  fi

  if ["x${GRUB_DISABLE_RECOVERY}" != "xtrue"]; then
    linux_entry "${OS}" "${version}" recovery standard \
                "single ${GRUB_CMDLINE_LINUX}"
  fi

  list=echo $list | tr ' ' '\n' | fgrep -vx "$linux" | tr '\n' ' '
done

# If at least one kernel was found, then we need to
# add a closing '}' for the submenu command.
if [x"$is_top_level" != xtrue]; then
  echo '}'
fi

echo "$title_correction_code"```

***This is 10_linux in rocky 8:***

#! /bin/sh
set -e

# grub-mkconfig helper script.
# Copyright (C) 2006,2007,2008,2009,2010 Free Software Foundation, Inc.
#
# GRUB is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GRUB is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GRUB. If not, see <http://www.gnu.org/licenses/>.

prefix="/usr"
exec_prefix="/usr"
datarootdir="/usr/share"

. "$pkgdatadir/grub-mkconfig_lib"

export TEXTDOMAIN=grub
export TEXTDOMAINDIR="${datarootdir}/locale"

CLASS="--class gnu-linux --class gnu --class os --unrestricted"

if ["x${GRUB_DISTRIBUTOR}" = "x"] ; then
  OS="$(eval $(grep PRETTY_NAME /etc/os-release) ; echo ${PRETTY_NAME})"
  CLASS="--class $(eval $(grep '^ID_LIKE=\|^ID=' /etc/os-release) ; [-n "${ID_LIKE}"] && echo ${ID_LIKE} || echo ${ID}) ${CLASS}"
else
  OS="${GRUB_DISTRIBUTOR}"
  CLASS="--class $(echo ${GRUB_DISTRIBUTOR} | tr 'A-Z' 'a-z' | cut -d' ' -f1|LC_ALL=C sed 's,[^[:alnum:]_],_,g') ${CLASS}"
fi

# loop-AES arranges things so that /dev/loop/X can be our root device, but
# the initrds that Linux uses don't like that.
case ${GRUB_DEVICE} in
  /dev/loop/*|/dev/loop[0-9])
    GRUB_DEVICE=losetup ${GRUB_DEVICE} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"
  ;;
esac

# Default to disabling partition uuid support to maintian compatibility with
# older kernels.
GRUB_DISABLE_LINUX_PARTUUID=${GRUB_DISABLE_LINUX_PARTUUID-true}

# btrfs may reside on multiple devices. We cannot pass them as value of root= parameter
# and mounting btrfs requires user space scanning, so force UUID in this case.
if ( ["x${GRUB_DEVICE_UUID}" = "x"] && ["x${GRUB_DEVICE_PARTUUID}" = "x"] ) \
    || ( ["x${GRUB_DISABLE_LINUX_UUID}" = "xtrue"] \
        && ["x${GRUB_DISABLE_LINUX_PARTUUID}" = "xtrue"] ) \
    || ( ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
        && ! test -e "/dev/disk/by-partuuid/${GRUB_DEVICE_PARTUUID}" ) \
    || ( test -e "${GRUB_DEVICE}" && uses_abstraction "${GRUB_DEVICE}" lvm ); then
  LINUX_ROOT_DEVICE=${GRUB_DEVICE}
elif ["x${GRUB_DEVICE_UUID}" = "x"] \
    || ["x${GRUB_DISABLE_LINUX_UUID}" = "xtrue"]; then
  LINUX_ROOT_DEVICE=PARTUUID=${GRUB_DEVICE_PARTUUID}
else
  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
fi

case x"$GRUB_FS" in
    xbtrfs)
        if ["x${SUSE_BTRFS_SNAPSHOT_BOOTING}" = "xtrue"]; then
        GRUB_CMDLINE_LINUX="${GRUB_CMDLINE_LINUX} \${extra_cmdline}"
        else
        rootsubvol="make_system_path_relative_to_its_root /"
        rootsubvol="${rootsubvol#/}"
        if ["x${rootsubvol}" != x]; then
            GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
        fi
        fi;;
    xzfs)
        rpool=${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || true
        bootfs="make_system_path_relative_to_its_root / | sed -e "s,@$,,""
        LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs}"
        ;;
esac

populate_header_warn()
{
cat <<EOF

# This section was generated by a script. Do not modify the generated file - all changes
# will be lost the next time file is regenerated. Instead edit the BootLoaderSpec files.
#
# The blscfg command parses the BootLoaderSpec files stored in /boot/loader/entries and
# populates the boot menu. Please refer to the Boot Loader Specification documentation
# for the files format: https://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/.

EOF
}

mktitle ()
{
  local title_type
  local version
  local OS_NAME
  local OS_VERS

  title_type=$1 && shift
  version=$1 && shift

  OS_NAME="$(eval $(grep ^NAME= /etc/os-release) ; echo ${NAME})"
  OS_VERS="$(eval $(grep ^VERSION= /etc/os-release) ; echo ${VERSION})"

  case $title_type in
    recovery)
      title=$(printf '%s (%s) %s (recovery mode)' \
                     "${OS_NAME}" "${version}" "${OS_VERS}")
      ;;
    *)
      title=$(printf '%s (%s) %s' \
                     "${OS_NAME}" "${version}" "${OS_VERS}")
      ;;
  esac
  echo -n ${title}
}

title_correction_code=

linux_entry ()
{
  os="$1"
  version="$2"
  type="$3"
  isdebug="$4"
  args="$5"

  if [-z "$boot_device_id"]; then
      boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
  fi

  if ["x${GRUB_ENABLE_BLSCFG}" = "xtrue"]; then
    if [x$dirname = x/]; then
      if [-z "${prepare_root_cache}"]; then
        prepare_grub_to_access_device ${GRUB_DEVICE}
      fi
    else
      if [-z "${prepare_boot_cache}"]; then
        prepare_grub_to_access_device ${GRUB_DEVICE_BOOT}
      fi
    fi

    if [-d /sys/firmware/efi]; then
        bootefi_device="${grub_probe} --target=device /boot/efi/"
        prepare_grub_to_access_device ${bootefi_device} boot
    else
        boot_device="${grub_probe} --target=device /boot/"
        prepare_grub_to_access_device ${boot_device} boot
    fi

    populate_header_warn

    cat << EOF
# The kernelopts variable should be defined in the grubenv file. But to ensure that menu
# entries populated from BootLoaderSpec files that use this variable work correctly even
# without a grubenv file, define a fallback kernelopts variable if this has not been set.
#
# The kernelopts variable in the grubenv file can be modified using the grubby tool or by
# executing the grub2-mkconfig tool. For the latter, the values of the GRUB_CMDLINE_LINUX
# and GRUB_CMDLINE_LINUX_DEFAULT options from /etc/default/grub file are used to set both
# the kernelopts variable in the grubenv file and the fallback kernelopts variable.
if [-z "\${kernelopts}"]; then
  set kernelopts="root=${linux_root_device_thisversion} ro ${args}"
fi

insmod blscfg
blscfg
EOF

    if ["x${GRUB_GRUBENV_UPDATE}" = "xyes"]; then
        ${grub_editenv} - set kernelopts="root=${linux_root_device_thisversion} ro ${args}"
    fi

    exit 0
  fi

  if [x$type != xsimple] ; then
      title=$(mktitle "$type" "$version")
      if [x"$title" = x"$GRUB_ACTUAL_DEFAULT"] || [x"Previous Linux versions>$title" = x"$GRUB_ACTUAL_DEFAULT"]; then
          replacement_title="$(echo "Advanced options for ${OS}" | sed 's,>,>>,g')>$(echo "$title" | sed 's,>,>>,g')"
          quoted="$(echo "$GRUB_ACTUAL_DEFAULT" | grub_quote)"
          title_correction_code="${title_correction_code}if [\"x\$default\" = '$quoted']; then default='$(echo "$replacement_title" | grub_quote)'; fi;"
      fi
      if [x$isdebug = xdebug]; then
          title="$title${GRUB_LINUX_DEBUG_TITLE_POSTFIX}"
      fi
      echo "menuentry '$(echo "$title" | grub_quote)' ${CLASS} \$menuentry_id_option 'gnulinux-$version-$type-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
  else
      echo "menuentry '$(echo "$os" | grub_quote)' ${CLASS} \$menuentry_id_option 'gnulinux-simple-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
  fi
  if [x$type != xrecovery] ; then
      save_default_entry | grub_add_tab
  fi

  # Use ELILO's generic "efifb" when it's known to be available.
  # FIXME: We need an interface to select vesafb in case efifb can't be used.
  if ["x$GRUB_GFXPAYLOAD_LINUX" = x]; then
      echo " load_video" | sed "s/^/$submenu_indentation/"
      if grep -qx "CONFIG_FB_EFI=y" "${config}" 2> /dev/null \
          && grep -qx "CONFIG_VT_HW_CONSOLE_BINDING=y" "${config}" 2> /dev/null; then
          echo " set gfxpayload=keep" | sed "s/^/$submenu_indentation/"
      fi
  else
      if ["x$GRUB_GFXPAYLOAD_LINUX" != xtext]; then
          echo " load_video" | sed "s/^/$submenu_indentation/"
      fi
      echo " set gfxpayload=$GRUB_GFXPAYLOAD_LINUX" | sed "s/^/$submenu_indentation/"
  fi

  echo " insmod gzio" | sed "s/^/$submenu_indentation/"

  if [x$dirname = x/]; then
    if [-z "${prepare_root_cache}"]; then
      prepare_root_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE} | grub_add_tab)"
    fi
    printf '%s\n' "${prepare_root_cache}" | sed "s/^/$submenu_indentation/"
  else
    if [-z "${prepare_boot_cache}"]; then
      prepare_boot_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE_BOOT} | grub_add_tab)"
    fi
    printf '%s\n' "${prepare_boot_cache}" | sed "s/^/$submenu_indentation/"
  fi
  sed "s/^/$submenu_indentation/" << EOF
        linux ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}
EOF
  if test -n "${initrd}" ; then
    initrd_path=
    for i in ${initrd}; do
      initrd_path="${initrd_path} ${rel_dirname}/${i}"
    done
    sed "s/^/$submenu_indentation/" << EOF
        initrd $(echo $initrd_path)
EOF
  fi
  if test -n "${fdt}" ; then
    sed "s/^/$submenu_indentation/" << EOF
        devicetree ${rel_dirname}/${fdt}
EOF
  fi
  sed "s/^/$submenu_indentation/" << EOF
}
EOF
}

machine=uname -m
case "x$machine" in
    xi?86 | xx86_64)
        list=
        for i in /boot/vmlinuz-* /vmlinuz-* /boot/kernel-* ; do
            if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
        done ;;
    *)
        list=
        for i in /boot/vmlinuz-* /boot/vmlinux-* /vmlinuz-* /vmlinux-* /boot/kernel-* ; do
                  if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
        done ;;
esac

if ["x${GRUB_ENABLE_BLSCFG}" = "xtrue"]; then
    for i in /boot/ostree/*/vmlinuz-* ; do
        if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
    done
fi

case "$machine" in
    i?86) GENKERNEL_ARCH="x86" ;;
    mips|mips64) GENKERNEL_ARCH="mips" ;;
    mipsel|mips64el) GENKERNEL_ARCH="mipsel" ;;
    arm*) GENKERNEL_ARCH="arm" ;;
    *) GENKERNEL_ARCH="$machine" ;;
esac

prepare_boot_cache=
prepare_root_cache=
boot_device_id=
title_correction_code=

# Extra indentation to add to menu entries in a submenu. We're not in a submenu
# yet, so it's empty. In a submenu it will be equal to '\t' (one tab).
submenu_indentation=""

is_top_level=true
while ["x$list" != "x"] ; do
  linux=version_find_latest $list
  if ["x${GRUB_ENABLE_BLSCFG}" != "xtrue"]; then
    gettext_printf "Found linux image: %s\n" "$linux" >&2
  fi

  basename=basename $linux
  dirname=dirname $linux
  rel_dirname=make_system_path_relative_to_its_root $dirname
  version=echo $basename | sed -e "s,^[^0-9]*-,,g"
  alt_version=echo $version | sed -e "s,\.old$,,g"
  linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"

  initrd_early=
  for i in ${GRUB_EARLY_INITRD_LINUX_STOCK} \
           ${GRUB_EARLY_INITRD_LINUX_CUSTOM}; do
    if test -e "${dirname}/${i}" ; then
      initrd_early="${initrd_early} ${i}"
    fi
  done

  initrd_real=
  for i in "initrd.img-${version}" "initrd-${version}.img" "initrd-${version}.gz" \
           "initrd-${version}" "initramfs-${version}.img" \
           "initrd.img-${alt_version}" "initrd-${alt_version}.img" \
           "initrd-${alt_version}" "initramfs-${alt_version}.img" \
           "initramfs-genkernel-${version}" \
           "initramfs-genkernel-${alt_version}" \
           "initramfs-genkernel-${GENKERNEL_ARCH}-${version}" \
           "initramfs-genkernel-${GENKERNEL_ARCH}-${alt_version}"; do
    if test -e "${dirname}/${i}" ; then
      initrd_real="${i}"
      break
    fi
  done

  initrd=
  if test -n "${initrd_early}" || test -n "${initrd_real}"; then
    initrd="${initrd_early} ${initrd_real}"

    initrd_display=
    for i in ${initrd}; do
      initrd_display="${initrd_display} ${dirname}/${i}"
    done
    if ["x${GRUB_ENABLE_BLSCFG}" != "xtrue"]; then
      gettext_printf "Found initrd image: %s\n" "$(echo $initrd_display)" >&2
    fi
  fi

  fdt=
  for i in "dtb-${version}" "dtb-${alt_version}"; do
    if test -f "${dirname}/${i}/${GRUB_DEFAULT_DTB}" ; then
      fdt="${i}/${GRUB_DEFAULT_DTB}"
      break
    fi
  done

  config=
  for i in "${dirname}/config-${version}" "${dirname}/config-${alt_version}" "/etc/kernels/kernel-config-${version}" ; do
    if test -e "${i}" ; then
      config="${i}"
      break
    fi
  done

  initramfs=
  if test -n "${config}" ; then
      initramfs=grep CONFIG_INITRAMFS_SOURCE= "${config}" | cut -f2 -d= | tr -d \"
  fi

  if test -z "${initramfs}" && test -z "${initrd_real}" ; then
    # "UUID=" and "ZFS=" magic is parsed by initrd or initramfs. Since there's
    # no initrd or builtin initramfs, it can't work here.
    if ["x${GRUB_DEVICE_PARTUUID}" = "x"] \
        || ["x${GRUB_DISABLE_LINUX_PARTUUID}" = "xtrue"]; then

        linux_root_device_thisversion=${GRUB_DEVICE}
    else
        linux_root_device_thisversion=PARTUUID=${GRUB_DEVICE_PARTUUID}
    fi
  fi

  if ["x${GRUB_DISABLE_SUBMENU}" = "xyes"] || ["x${GRUB_DISABLE_SUBMENU}" = "xy"]; then
    GRUB_DISABLE_SUBMENU="true"
  fi

  if ["x$is_top_level" = xtrue] && ["x${GRUB_DISABLE_SUBMENU}" != xtrue]; then
    linux_entry "${OS}" "${version}" simple standard \
    "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
    if ["x$GRUB_LINUX_MAKE_DEBUG" = "xtrue"]; then
      linux_entry "${OS}" "${version}" simple debug \
        "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} ${GRUB_CMDLINE_LINUX_DEBUG}"
    fi

    submenu_indentation="$grub_tab"

    if [-z "$boot_device_id"]; then
        boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
    fi
    # TRANSLATORS: %s is replaced with an OS name
    echo "submenu '$(gettext_printf "Advanced options for %s" "${OS}" | grub_quote)' \$menuentry_id_option 'gnulinux-advanced-$boot_device_id' {"
    is_top_level=false
  fi

  linux_entry "${OS}" "${version}" advanced standard \
              "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
  if ["x$GRUB_LINUX_MAKE_DEBUG" = "xtrue"]; then
    linux_entry "${OS}" "${version}" advanced debug \
                "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} ${GRUB_CMDLINE_LINUX_DEBUG}"
  fi

  if ["x${GRUB_DISABLE_RECOVERY}" != "xtrue"]; then
    linux_entry "${OS}" "${version}" recovery standard \
                "single ${GRUB_CMDLINE_LINUX}"
  fi

  list=echo $list | tr ' ' '\n' | fgrep -vx "$linux" | tr '\n' ' '
done

# If at least one kernel was found, then we need to
# add a closing '}' for the submenu command.
if [x"$is_top_level" != xtrue]; then
  echo '}'
fi

echo "$title_correction_code"
````

---

<div class="post-metadata">

**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\
**Post date:** [May 21, 2025, 8:09pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/10 "2025-05-21T20:09:03Z")

</div>

First, the files look identical. Please show the _diff_ of them (if they do differ).

Second, the value of GRUB\_ENABLE\_BLSCFG is _read_, but not apparently written/changed in `10_linux`.

Third, the `/etc/default/grub` is used by `grub2-mkconfig` (which uses the `/etc/grub.d/` scripts to do the work). The work is to create `grub.cfg`. Update of packages does not call `grub2-mkconfig`, AFAIK. Install of new kernel does probably use `grubby` to _modify_ the grub.cfg (if BLS is not used).

---

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 22, 2025, 12:18pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/11 "2025-05-22T12:18:05Z")

</div>

I understand what you’re saying, but I’m experiencing this issue **only on Rocky Linux 8** , not on Red Hat 8. I would expect identical behavior between the two distributions.

Indeed, the two files are the same, but I don’t know where else to look for the issue.

With every update, the `GRUB_ENABLE_BLSCFG` entry gets overwritten to `false`, and I can’t figure out why…  
This prevents me from using the **serial console on AWS** , which is critical for my setup.

---

<div class="post-metadata">

**Author:** ![Vittory003](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/vittory003/32/4694_2.png) [@Vittory003](https://forums.rockylinux.org/u/Vittory003)\
**Post date:** [May 23, 2025, 12:54pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/12 "2025-05-23T12:54:35Z")

</div>

When I rebuild GRUB with new parameters adapted for the AWS serial console, the `grub2-mkconfig` utility fails to modify the files under `/boot/loader/entries`.  
This is why setting `GRUB_ENABLE_BLSCFG=true` does not work, and I have to manually set it to false.

On RHEL8, `grub2-mkconfig` also updates `/boot/loader/entries`, so it works correctly with `GRUB_ENABLE_BLSCFG=true`.

In short, on Rocky Linux, `grub2-mkconfig` is unable to expand the parameters in `GRUB_CMDLINE_LINUX` into the config files under `/boot/loader/entries`.  
Therefore, after the rebuild, `GRUB_ENABLE_BLSCFG=true` is ignored.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex020/uploads/rockylinux/original/1X/91b7219eec10e30013422e4df76c1d898711a5d5.svg) [@system](https://forums.rockylinux.org/u/system)\
**Post date:** [July 22, 2025, 12:55pm UTC](https://forums.rockylinux.org/t/how-to-prevent-changes-of-grub-enable-blscfg-in-etc-default-grub/18505/13 "2025-07-22T12:55:29Z")

</div>

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