grub2

Show grub2 menu on bootup:

# grub2-editenv list
saved_entry=0
menu_auto_hide=1
boot_success=1
boot_indeterminate=0

# grub2-editenv - set menu_auto_hide=1
# grub2-editenv - unset menu_auto_hide

# grub2-editenv list
saved_entry=0
boot_success=1
boot_indeterminate=0

# grubby --info=ALL
index=0
kernel="/boot/vmlinuz-6.15.6"
args="ro rootflags=subvol=root rhgb quiet $tuned_params"
root="UUID=f6b181fb-377d-4321-a31f-3e90f29a6abb"
initrd="/boot/initramfs-6.15.6.img $tuned_initrd"
title="Fedora Linux (6.15.6) 42 (Workstation Edition)"
id="226a800694a546aa9be2a9ad7d9a9ba9-6.15.6"
index=1
kernel="/boot/vmlinuz-6.14.0-63.fc42.x86_64"
args="ro rootflags=subvol=root rhgb quiet $tuned_params"
root="UUID=f6b181fb-377d-4321-a31f-3e90f29a6abb"
initrd="/boot/initramfs-6.14.0-63.fc42.x86_64.img $tuned_initrd"
title="Fedora Linux (6.14.0-63.fc42.x86_64) 42 (Workstation Edition)"
id="226a800694a546aa9be2a9ad7d9a9ba9-6.14.0-63.fc42.x86_64"
index=2
kernel="/boot/vmlinuz-0-rescue-226a800694a546aa9be2a9ad7d9a9ba9"
args="ro rootflags=subvol=root rhgb quiet"
root="UUID=f6b181fb-377d-4321-a31f-3e90f29a6abb"
initrd="/boot/initramfs-0-rescue-226a800694a546aa9be2a9ad7d9a9ba9.img"
title="Fedora Linux (0-rescue-226a800694a546aa9be2a9ad7d9a9ba9) 42 (Workstation Edition)"
id="226a800694a546aa9be2a9ad7d9a9ba9-0-rescue"

# grubby --remove-kernel=/boot/vmlinuz-6.15.6 

# grubby --info=ALL
index=0
kernel="/boot/vmlinuz-6.14.0-63.fc42.x86_64"
args="ro rootflags=subvol=root rhgb quiet $tuned_params"
root="UUID=f6b181fb-377d-4321-a31f-3e90f29a6abb"
initrd="/boot/initramfs-6.14.0-63.fc42.x86_64.img $tuned_initrd"
title="Fedora Linux (6.14.0-63.fc42.x86_64) 42 (Workstation Edition)"
id="226a800694a546aa9be2a9ad7d9a9ba9-6.14.0-63.fc42.x86_64"
index=1
kernel="/boot/vmlinuz-0-rescue-226a800694a546aa9be2a9ad7d9a9ba9"
args="ro rootflags=subvol=root rhgb quiet"
root="UUID=f6b181fb-377d-4321-a31f-3e90f29a6abb"
initrd="/boot/initramfs-0-rescue-226a800694a546aa9be2a9ad7d9a9ba9.img"
title="Fedora Linux (0-rescue-226a800694a546aa9be2a9ad7d9a9ba9) 42 (Workstation Edition)"
id="226a800694a546aa9be2a9ad7d9a9ba9-0-rescue"

# grub2-editenv list
saved_entry=1
boot_success=1
boot_indeterminate=0

# grub2-set-default 0

# grub2-editenv list
saved_entry=0
boot_success=1
boot_indeterminate=0

# cat /etc/default/grub
GRUB_TIMEOUT=30
...
GRUB_TERMINAL_OUTPUT="gfxterm"
GRUB_ENABLE_BLSCFG=true
GRUB_GFXMODE="1920x1080x32,auto"
GRUB_BACKGROUND=/boot/grub2/torres_del.png
GRUB_FONT=/boot/grub2/fonts/DejaVuSansMono24.pf2

# magick torres_del.png /boot/grub2/torres_del.png

# dnf install texlive-dejavu
# grub2-mkfont --output=/boot/grub2/fonts/DejaVuSansMono24.pf2 --size=24 \
   /usr/share/texlive/texmf-dist/fonts/truetype/public/dejavu/DejaVuSansMono.ttf

update "/etc/grub.d/06_local_colors" as per how-do-i-change-the-font-colours-for-grub
echo "${1}set color_normal=red/black"
echo "${1}set color_highlight=cyan/light-gray"
echo "${1}set menu_color_normal=blue/black"
echo "${1}set menu_color_highlight=green/light-gray"

# grub2-mkconfig -o /boot/grub2/grub.cfg