From Forum Nokia Wiki

Overview

Some handsets, such as fold phones, have two screens. One screen (mini screen) is visible when the phone is closed and the other screen (main screen) is visible only after you open the phone. Often, the mini screen also has reduced functionality. Series 40 themes allows you to set some theme elements to have different values on the mini screen than on the main screen.

How to customize the Mini Screen of S40 Devices using Carbide.ui

The Mini Screen option in Carbide.Carbide.ui Series 40 theme allows you to customize various elements on the mini screen.

After importing or creating the s40 Theme in carbide.ui, you will find a Mini Screen option in the resources view.

The Mini Screen tab contains two sub-options: Colors (Mini) and Images (Mini).

The elements on the sub-options are the same as their main screen equivalents, except that they are applied only to elements displayed on the second screen.

The mini screen elements are all color elements and full-screen images. Typically, if you do not select a specific wallpaper, screen saver, or background for a mini screen, the handset applies the wallpaper, screen saver, and background element (respectively) of the main screen to the mini screen. If no value is defined for the main screen, the handset uses the build-in default.