append
GRUB_GFXMODE="800x600" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
to /etc/default/grub
# grub2-mkconfig -o /boot/grub2/grub.cfg
append
GRUB_GFXMODE="800x600" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
to /etc/default/grub
# grub2-mkconfig -o /boot/grub2/grub.cfg