Cannot get system to boot older kernel w/ grubby

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vtwin@cox.net
Posts: 30
Joined: 2017/02/16 16:41:29

Cannot get system to boot older kernel w/ grubby

Post by vtwin@cox.net » 2020/04/18 19:54:13

Have two kernels installed on my system:

# ls -l /boot/vm*

-rwxr-xr-x 1 root root 8106744 Apr 9 09:56 /boot/vmlinuz-4.18.0-147.8.1.el8_1.x86_64
-rwxr-xr-x 1 root root 8612224 Jan 26 20:48 /boot/vmlinuz-5.5.0-1.el8.elrepo.x86_64

currently I am booting 5.5, I want to boot 4.18, so I execute

# grubby --set-default=/boot/vmlinuz-4.18.0-147.8.1.el8_1.x86_64

The default is /boot/loader/entries/9a4d979503d9444497e6f644a4e6f313-4.18.0-147.8.1.el8_1.x86_64.conf with index 1 and kernel /boot/vmlinuz-4.18.0-147.8.1.el8_1.x86_64

# grubby --default-kernel

/boot/vmlinuz-4.18.0-147.8.1.el8_1.x86_64

# grubby --default-index
1

(init 6, reboot, re-login)

# uname -a

Linux x.y.z 5.5.0-1.el8.elrepo.x86_64 #1 SMP Sun Jan 26 20:30:48 EST 2020 x86_64 x86_64 x86_64 GNU/Linux


How can I force the system to boot 4.18?

/boot/grub2/grub.cfg:

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
set pager=1

if [ -f ${config_directory}/grubenv ]; then
load_env -f ${config_directory}/grubenv
elif [ -s $prefix/grubenv ]; then
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="${saved_entry}"
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 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
}

terminal_output console
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/00_tuned ###
set tuned_params=""
set tuned_initrd=""
### END /etc/grub.d/00_tuned ###

### BEGIN /etc/grub.d/01_menu_auto_hide ###
if [ "${boot_success}" = "1" -o "${boot_indeterminate}" = "1" ]; then
set last_boot_ok=1
else
set last_boot_ok=0
fi

# Reset boot_indeterminate after a successful boot
if [ "${boot_success}" = "1" ] ; then
set boot_indeterminate=0
# Avoid boot_indeterminate causing the menu to be hidden more then once
elif [ "${boot_indeterminate}" = "1" ]; then
set boot_indeterminate=2
fi
set boot_success=0
save_env boot_success boot_indeterminate

if [ x$feature_timeout_style = xy ] ; then
if [ "${menu_show_once}" ]; then
unset menu_show_once
save_env menu_show_once
set timeout_style=menu
set timeout=60
elif [ "${menu_auto_hide}" -a "${last_boot_ok}" = "1" ]; then
set orig_timeout_style=${timeout_style}
set orig_timeout=${timeout}
if [ "${fastboot}" = "1" ]; then
# timeout_style=menu + timeout=0 avoids the countdown code keypress check
set timeout_style=menu
set timeout=0
else
set timeout_style=hidden
set timeout=1
fi
fi
fi
### END /etc/grub.d/01_menu_auto_hide ###

### BEGIN /etc/grub.d/01_users ###
if [ -f ${prefix}/user.cfg ]; then
source ${prefix}/user.cfg
if [ -n "${GRUB2_PASSWORD}" ]; then
set superusers="root"
export superusers
password_pbkdf2 root ${GRUB2_PASSWORD}
fi
fi
### END /etc/grub.d/01_users ###

### BEGIN /etc/grub.d/10_linux ###
insmod part_msdos
set boot='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=boot --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 bca86349-85b2-4b4e-b449-25cd7ee90c0f
else
search --no-floppy --fs-uuid --set=boot bca86349-85b2-4b4e-b449-25cd7ee90c0f
fi

# 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/Specif ... oaderSpec/.

insmod blscfg
blscfg
if [ -s $prefix/grubenv ]; then
load_env
fi
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_tboot ###
### END /etc/grub.d/20_linux_tboot ###

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

### BEGIN /etc/grub.d/20_linux_xen_tboot ###
### END /etc/grub.d/20_linux_xen_tboot ###

### BEGIN /etc/grub.d/20_ppc_terminfo ###
### END /etc/grub.d/20_ppc_terminfo ###

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

### BEGIN /etc/grub.d/30_uefi-firmware ###
### END /etc/grub.d/30_uefi-firmware ###

### 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 ###

### BEGIN /etc/grub.d/42_boom ###
### END /etc/grub.d/42_boom ###


/boot/grub2/grubenv

# GRUB Environment Block
saved_entry=9a4d979503d9444497e6f644a4e6f313-4.18.0-147.8.1.el8_1.x86_64
kernelopts=root=UUID=f9e71357-2dad-4644-b88f-9fe413247d8c ro rhgb quiet
boot_success=0
######################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################[r

vtwin@cox.net
Posts: 30
Joined: 2017/02/16 16:41:29

Re: Cannot get system to boot older kernel w/ grubby

Post by vtwin@cox.net » 2020/05/14 11:48:03

bump.

anyone? any ideas? still can't get this to work.

tunk
Posts: 760
Joined: 2017/02/22 15:08:17

Re: Cannot get system to boot older kernel w/ grubby

Post by tunk » 2020/05/14 12:22:54

Are you able to select 4.18 from the GRUB boot menu?

vtwin@cox.net
Posts: 30
Joined: 2017/02/16 16:41:29

Re: Cannot get system to boot older kernel w/ grubby

Post by vtwin@cox.net » 2020/05/14 12:28:40

No, its a machine at a location which is in shutdown and there is no employee access, only remote access. So physical access to the machine is not a possibility at this time, unfortunately, that would make my life easy.

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