How to fix the boot screen resolution in Ubuntu.

Some people, after installing Ubuntu Linux, see the decision of the startup screen (boot GUI) is not appropriate for the resolution of the monitor set in the system.
Here I'll show you a way to correct the usplash resolution to match the set in the system.

1. Open a terminal and type:

sudo gedit /etc/usplash.conf

The sudo command will ask for your password so you can edit the file with administrator permissions.
Usplash.conf to open the file you'll see something like this:

# Configuration file Usplash
# These parameters will only apply after running update-initramfs.
Xres = 640
Yres = 480

Or maybe just:

# Configuration file Usplash
# These parameters will only apply after running update-initramfs.

2. Sets Xres and Yres the resolution you want, for example 1024 × 768.

# Configuration file Usplash
# These parameters will only apply after running update-initramfs.
Xres = 1024
Yres = 768

And save your changes.
3. Now you must update your initramfs for the changes to take effect:

sudo update-initramfs -u

Note: Restarting the computer can see the boot screen with the new resolution.