Silent Grub

vi /etc/default/grub

GRUB_DEFAULT=0
#GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash vga=current loglevel=0 rd.systemd.show_status=false rd.udev.log_priority=3 vt.global_cursor_default=0"
#/sys/class/drm/card0-DP-1/edid
#GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=DP-1:1920x1080@60D drm_kms_helper.edid_firmware=DP-1:edid/edid.bin"
GRUB_CMDLINE_LINUX="quiet splash vga=current loglevel=0 rd.systemd.show_status=false rd.udev.log_priority=3 vt.global_cursor_default=0"
#GRUB_GFXPAYLOAD_LINUX=auto
GRUB_TERMINAL=console
#GRUB_GFXMODE="1920x1080x32"
#GRUB_GFXMODE=1920x1080,1024x768x32,auto
GRUB_GFXPAYLOAD_LINUX="keep"
GRUB_DISABLE_OS_PROBER=true
# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=1920x1080
#640x480

GRUB_GFXPAYLOAD_LINUX=“keep” - keeps the resolution and avoids plymouth flickering
GRUB_CMDLINE_LINUX=“quiet” - lowers log level and boot output
GRUB_CMDLINE_LINUX=“splash” - shows plymouth splash screen/animation if installed
GRUB_CMDLINE_LINUX=“vga=current” - keeps current vga resolution - other values in table below
GRUB_CMDLINE_LINUX=“loglevel=0 rd.systemd.show_status=false rd.udev.log_priority=3” - lowers loglevel even further than quiet
GRUB_CMDLINE_LINUX=“vt.global_cursor_default=0” - disable blinking cursor

sudo update-grub

After a boot entry has been selected in GRUB2, for a short time (1-2 sec) another screen is displayed which shows:

Loading linux...
Loading initial ramdisk ...

To suppress this output, edit /etc/grub.d/10_linux

quiet_boot=0
and comment out all instances of:
#  if [ x"$quiet_boot" = x0 ] || [ x"$type" != xsimple ]; then
#    message="$(gettext_printf "Loading Linux %s ..." ${version})"
#    sed "s/^/$submenu_indentation/" << EOF
#       echo    '$(echo "$message" | grub_quote)'
#EOF
#  fi

then
sudo update-grub

Available VGA Modes: