As @MaMicha appears to want what is almost a default GRUB boot process (with just a change to no splash and the Manjaro theme), they might be best off just replacing their /etc/default/grub file with the following (which is just the file from the latest GRUB package with the Manjaro theme path inserted, the removal of quiet so that text appears during the boot process, and Plymouth disabled using kernel parameters):
# GRUB boot loader configuration
GRUB_DEFAULT=saved
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="Manjaro"
GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 rd.udev.log_level=3"
GRUB_CMDLINE_LINUX="plymouth.enable=0 disablehooks=plymouth"
# Preload both GPT and MBR modules so that they are not missed
GRUB_PRELOAD_MODULES="part_gpt part_msdos"
# Uncomment to enable booting from LUKS encrypted devices
#GRUB_ENABLE_CRYPTODISK=y
# Set to 'countdown' or 'menu' to change timeout behavior,
# press ESC key to display menu.
GRUB_TIMEOUT_STYLE=hidden
# Uncomment to use basic console
GRUB_TERMINAL_INPUT=console
# Uncomment to disable graphical terminal
#GRUB_TERMINAL_OUTPUT=console
# 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 'videoinfo'
GRUB_GFXMODE=auto
# Uncomment to allow the kernel use the same resolution used by grub
GRUB_GFXPAYLOAD_LINUX=keep
# Uncomment if you want GRUB to pass to the Linux kernel the old parameter
# format "root=/dev/xxx" instead of "root=/dev/disk/by-uuid/xxx"
#GRUB_DISABLE_LINUX_UUID=true
# Uncomment to disable generation of recovery mode menu entries
GRUB_DISABLE_RECOVERY=true
# Uncomment and set to the desired menu colors. Used by normal and wallpaper
# modes only. Entries specified as foreground/background.
GRUB_COLOR_NORMAL="light-gray/black"
GRUB_COLOR_HIGHLIGHT="green/black"
# Uncomment one of them for the gfx desired, a image background or a gfxtheme
#GRUB_BACKGROUND="/usr/share/grub/background.png"
GRUB_THEME="/usr/share/grub/themes/manjaro/theme.txt"
# Uncomment to get a beep at GRUB start
#GRUB_INIT_TUNE="480 440 1"
# Uncomment to make GRUB remember the last selection. This requires
# setting 'GRUB_DEFAULT=saved' above.
GRUB_SAVEDEFAULT=true
# Uncomment to disable submenus in boot menu
#GRUB_DISABLE_SUBMENU=y
# Uncomment this option to enable os-prober execution in the grub-mkconfig command
#GRUB_DISABLE_OS_PROBER=false
# Uncomment to ensure that the root filesystem is mounted read-only so that
# systemd-fsck can run the check automatically. We use 'fsck' by default, which
# needs 'rw' as boot parameter, to avoid delay in boot-time. 'fsck' needs to be
# removed from 'mkinitcpio.conf' to make 'systemd-fsck' work.
# See also Arch-Wiki: https://wiki.archlinux.org/title/Fsck#Boot_time_checking
#GRUB_ROOT_FS_RO=true
# Disable generating menu entries for other EFI boot manager entries detected
GRUB_DISABLE_BOOTNEXT=true
# Skip EFI boot manager entries that are marked inactive
# when when generating bootnext entries
GRUB_BOOTNEXT_OMIT_INACTIVE=true
I recommend that you make the changes by opening the file in a GUI text editor (as you use Plasma, kate):
kate /etc/default/grub
Just replace the entire contents of the file with the content from above. When you click the Save button, you will be prompted to enter your password to save the file.
Then, run:
sudo update-grub
and reboot.
If you decide at some stage that you do want to see a menu (which is useful when multiple kernels are installed, especially release candidates where you may occasionally need to boot into a more stable kernel), then you should change the GRUB_TIMEOUT_STYLE=hidden entry to GRUB_TIMEOUT_STYLE=menu, and also probably make the timeout a bit longer so that you have enough time to select the kernel.
This will set the timeout to 15 seconds: GRUB_TIMEOUT=15, which is what I have set on my system. If I don’t want to wait 15 seconds, I just press Enter when the grub menu appears to immediately boot into the latest kernel .
Of course, sudo update-grub needs to be run whenever any changes are made to /etc/default/grub.
Once you are happy with your grub configuration, you should then remove the .pacnew file:
sudo rm /etc/default/grub.pacnew