For that, I just had to do the following:
(Please continue at your own risk)
Launched the terminal (Accessories > Terminal) and typed in sudo dpkg-reconfigure grub-pc. I left the linux command line field empty and hit enter.
In Linux default command line, there was “quiet” already. So I added “splash”(without quotes) after a space.

Then I pressed enter and again enter. I chose the default in Grub Install Devices and pressed enter again.
It gave me:

1

Installation finished. No error reported.

and then generated grub.cfg.

Then, I typed in

1

sudo plymouth-set-default-theme --list

and pressed enter. It gives a list of installed themes for plymouth. To set, you can use

2

sudo plymouth-set-default-theme THEME_NAME --rebuild-initrd

where THEME_NAME is the one listed by the previous command. I chose solar by typing in:

2

sudo plymouth-set-default-theme solar --rebuild-initrd

and rebooted. I could see plymouth now. The solar theme looks great.

Your graphics card may not be compatible with Plymouth, so don’t expect it to work, not so early. I hope it supports yours in later developments.

Please share your Plymouth experience.

Related posts:

1. [SOLVED] LTSP, “error: LTSP client installation ended abnormally”
2. [SOLVED] “subprocess pre-removal script returned error exit status 2″ error
3. [SOLVED] Unable to get Exclusive Lock Problem While Launching Synaptic, /var/lib/dpkg/lock – open (11 Resource temporarily unavailable) Error
4. [SOLVED] ‘Murrine configuration option “scrollbar_color”, “gradients” is no longer supported and will be ignored.’
5. [SOLVED] Gtk-Message: Failed to load module “gnomenu-panel”