검은색 화면/부팅 중단

linux /boot/vmlinuz-... root=... quiet splash nomodeset

Ctrl + Alt + F2 (F2 through F6 all work)

# Check NVIDIA driver status
nvidia-smi
 
# If the driver has issues, remove the proprietary driver to fall back to the
# kernel's built-in nouveau driver (nouveau is a kernel driver — no separate
# X.org driver package is needed)
sudo apt purge 'nvidia-*'
sudo apt autoremove
sudo reboot

sudo dmesg | grep -i amdgpu
# Try adding to GRUB: amdgpu.dc=0

sudo dmesg | grep -i i915
# Try kernel parameter: i915.enable_psr=0

# Check GDM status
systemctl status gdm3
 
# Restart GDM
sudo systemctl restart gdm3
 
# If GDM is corrupted, reinstall it
sudo apt install --reinstall gdm3
 
# Or temporarily switch to LightDM
sudo apt install lightdm
sudo dpkg-reconfigure lightdm

# Regenerate the initramfs (Ubuntu 26.04 uses Dracut by default)
sudo dracut -f --regenerate-all
# If your system still uses the legacy initramfs-tools, use instead:
# sudo update-initramfs -u -k all
 
# Update GRUB
sudo update-grub

# In recovery mode or from Live USB
sudo fsck -y /dev/sdXn

# Mount the system partition
sudo mount /dev/sdX2 /mnt
sudo mount /dev/sdX1 /mnt/boot/efi  # EFI partition
sudo mount --bind /dev /mnt/dev
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
 
# chroot into the installed system
sudo chroot /mnt
 
# Repair inside chroot
apt update
apt install --reinstall linux-generic
# Ubuntu 26.04 generates the initramfs with Dracut by default:
dracut -f --regenerate-all
# On legacy initramfs-tools systems use instead: update-initramfs -u -k all
update-grub
 
# Exit
exit
sudo umount -R /mnt
sudo reboot

# View the last (failed) boot log
journalctl -b -1
 
# Show only errors
journalctl -b -1 -p err
 
# View graphics-related logs
journalctl -b -1 | grep -i "gdm\|gnome\|wayland\|xorg"