rescue kernel:

 

to remove/refresh it:

 

# -- not reading from stdin

RESKERN=`echo  /boot/vmlinuz-0-rescue-*`

grubby --remove-kernel=$RESKERN

rm /boot/*rescu*

 

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

 

 

# make sure You can install the right version for Your rescue kernel:

dnf update kernel

# which will create a rescue kernel in this version

 

# BUG-fix

# =======

RESKERN=`echo  /boot/vmlinuz-0-rescue-*`

TITLE=`grubby --info=$RESKERN | grep title|sed 's/title=//g'`

# e.g.: title="Fedora (0-rescue-af83f4e90dfa42568ef69bc637593542) 30 (Thirty)"

grubby --remove-kernel=$RESKERN

grubby --add-kernel=$RESKERN  --title="$TITLE"

# check

grubby --info=ALL

# update bootloader

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

 

 

# never a rescue kernel again ....

dnf erase dracut-config-rescue

 

 

 

-- INFO --

grubby --info=ALL

-- WRONG

kernel="/vmlinuz-0-rescue-af83f4e90dfa42568ef69bc637593542"

...

initrd="/initramfs-0-rescue-af83f4e90dfa42568ef69bc637593542.img"

 

-- CORRECT after BUG-fix

kernel="/boot/vmlinuz-0-rescue-af83f4e90dfa42568ef69bc637593542"

...

initrd="/boot/initramfs-0-rescue-af83f4e90dfa42568ef69bc637593542.img"

 

 

-- UTILS --

grubby --default-kernel

grubby --default-index

grubby --set-default /boot/vmlinuz-5.1.15-300.fc30.x86_64

 

 

 

 

-- UTILS 2 ---

# ----

# GRUB_ENABLE_BLSCFG=true ... in /etc/default/grub

#    if set to true then:

#    modify kernel arguments by

grub2-editenv - set kernelopts="root=/dev/mapper/VGROOT-LVROOT ro resume=/dev/mapper/VGROOT-LVSWAP rd.lvm.lv=VGROOT/LVROOT rd.lvm.lv=VGROOT/LVSWAP nomodeset biosdevname=0 net.ifnames=0 "

# check

grub2-editenv - list | grep kernelopts