#!/bin/bash

[ ! -f /etc/default/grub ] && exit 1

sed 's/^GRUB_THEME/#GRUB_THEME/' -i /etc/default/grub
sed '/GRUB_CMDLINE_LINUX/s/rhgb quiet/nomodeset crashkernel=0/' -i /etc/default/grub
sed '/^GRUB_TERMINAL_OUTPUT=/d' -i /etc/default/grub
sed '/^GRUB_GFXMODE=/d' -i /etc/default/grub
sed '/^GRUB_GFXPAYLOAD_LINUX=/d' -i /etc/default/grub

cat >>/etc/default/grub <<END
GRUB_TERMINAL_OUTPUT="console"
GRUB_GFXMODE="text"
GRUB_GFXPAYLOAD_LINUX="text"
END

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