The Problem

The blue Plymouth splash screen between GRUB and GDM comes from Debian's branding. While harmless, it creates a jarring visual transition and obscures the clean boot experience many professionals prefer.

Current Boot Sequence: GRUB → Blue Plymouth Screen → LUKS Prompt → GDM

Why Remove Plymouth?

  • ✓ Cleaner aesthetics — No jarring color transitions
  • ✓ Professional appearance — Black screen looks more polished
  • ✓ Custom GRUB themes — Your branding is visible longer
  • ✓ Faster boot perception — No splash animation delays
  • ✓ LUKS compatibility — Encryption prompt works properly

Step 1: Remove Plymouth Packages

bash
sudo apt purge plymouth plymouth-themes
sudo apt autoremove

Step 2: Update GRUB Configuration

Edit /etc/default/grub and remove splash parameters:

/etc/default/grub
# Change this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

# To this (clean black screen):
GRUB_CMDLINE_LINUX_DEFAULT="quiet"

# Or this (show boot messages):
GRUB_CMDLINE_LINUX_DEFAULT=""

Step 3: Disable Debian Theme Script

The 05_debian_theme script sets the blue background. Remove execute permissions:

bash
sudo chmod -x /etc/grub.d/05_debian_theme
Why chmod and not delete? Package updates won't complain, and you can easily reverse the change if needed.

Step 4: Apply Changes

bash
sudo update-grub
sudo update-initramfs -u -k all
sudo reboot

Result: Clean Boot Sequence

New Boot Sequence: Custom GRUB → Black Screen → LUKS Prompt → GDM 🎉

Your boot sequence is now clean and professional. The custom GRUB theme remains visible, then transitions directly to a black screen (or kernel messages if you removed "quiet"), then your LUKS encryption prompt and finally GDM.

Verification

Confirm the Debian theme script is being skipped:

bash
# Check grub.cfg - should show empty section
grep -A2 "05_debian_theme" /boot/grub/grub.cfg

# Verify Plymouth is gone
which plymouth
# Should return: "no plymouth in..."

Reversing the Change

If you want the blue screen back:

bash
sudo chmod +x /etc/grub.d/05_debian_theme
sudo apt install plymouth plymouth-themes
sudo update-grub
sudo update-initramfs -u -k all