All notes
Grub

Intro

Fix grub on ubuntu

Ref.

# See disk info.
sudo fdisk -l
sudo blkid

# Mount.
sudo mount /dev/sdX1 /mnt

sudo grub-install --boot-directory=/mnt/boot /dev/sdX

# Probe windows bootloader.
sudo update-grub

Grub UEFI

mkdir -p /boot/efi
mount -t vfat /dev/sdXY /boot/efi
# Where X is your boot hard disk and Y is the efi partition you created earlier.
# Install GRUB UEFI application to and its modules to /boot/grub/x86_64-efi using:
modprobe dm-mod
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=arch_grub --recheck --debug
mkdir -p /boot/grub/locale
cp /usr/share/locale/en\@quot/LC_MESSAGES/grub.mo /boot/grub/locale/en.mo
# Generate a configuration for GRUB
grub-mkconfig -o /boot/grub/grub.cfg

Kernel options

Redhat.

Disabling modesetting

ArchWiki. You may want to disable KMS for various reasons, such as getting a blank screen or a "no signal" error from the display, when using the Catalyst driver, etc. To disable KMS add nomodeset as a kernel parameter. See Kernel parameters for more info. Along with nomodeset kernel parameter, for Intel graphics card you need to add i915.modeset=0 and for Nvidia graphics card you need to add nouveau.modeset=0. For Nvidia Optimus dual-graphics system, you need to add all the three kernel parameters (i.e. "nomodeset i915.modeset=0 nouveau.modeset=0").