The 2017 version of u-boot supports showing a splash screen. This is stored as a bmp file in the same partition as the kernel and can be easily modified without rebuilding the kernel.

Note the the splash image takes several seconds to appear when using HDMI.  LVDS panels show the image in under 0.5 second, depending on the size of the image.

Splash Image Specification

The image used for the splash screen must be a 24-bpp bitmap.  16-bpp images are not supported.

Environment Variables

Set the following variables to enable the splash screen:

The splashpos variable centers the image.  Other values can be added.

Loading the Splash Image

u-boot looks for a file called splash.bmp in the same partition as the kernel.

To load via USB: