grub2 - How to remove graphical noise at ThinkPad boot splash?

I have installed KDE Neon (Ubuntu 18.04 with newer KDE backport ).
It works fine, but I have one small problem:

When I boot, I get the Thinkpad BIOS bootscreen:

And right afterwards, I get the below for a few seconds

Afterwards, the Plymouth slash screen appears, and everything boots as expected.

Now my question:

I want to know what the problem is.
I looked in dmesg, and found nothing extraordinary.

This seems to be in place of the kernel splash screen with the Tux icon, I presume.

• A) What is causing this screen ?



• B) Is this a kernel/driver or a plymouth malfunction ?


• C) Is there a proper name for this pixel noise ?


• D) If the log is not in dmesg, where is it ?


• E) How can I get rid of it ?

Ah, figured it out myselfs.
For some hardware, it's necessary to set some kernel parameters, in order for the boot process to work correctly.

In this case, nomodeset.
It's called a corrupted splash screen.

To fix it, open /etc/default/grub, and add nomodeset to GRUB_CMDLINE_LINUX_DEFAULT:

GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
GRUB_CMDLINE_LINUX=""

and then, run:

sudo update-grub

If nomodeset creates bootup problems, alternatively just remove splash from GRUB_CMDLINE_LINUX_DEFAULT.