Plymouth

Change theme in Ubuntu 20.04.

Installation

Download the folder and copy to /usr/share/plymouth/themes.

cp -r new_plymouth_folder /usr/share/plymouth/themes

Install the new Plymouth theme as the default theme using the command below.

sudo update-alternatives --install
/usr/share/plymouth/themes/default.plymouth default.plymouth
/usr/share/plymouth/themes/new_plymouth_folder/new_plymouth.plymouth 100

Change the default theme to yours by entering the theme number.

sudo update-alternatives --config default.plymouth

For the changes take effect run the following command.

sudo update-initramfs -u