I think you mean authenticate the kernel. Is that correct? If you want
to do that, U-Boot has that capability. You can do all of this in a script
that will either boot the authenticated kernel or display a splash
For the splash screen, there are several ways to do it. One way would
use a U-Boot command, depending on version, to display a bitmap stored in
flash or on an SD card. The other way would require you to convert a bitmap
to a header file and rebuild the U-Boot image. I can give you directions
for this if you tell me where you want to store the image and what version
of U-Boot you are using. Also for rebuilding the image, you will need to
know which source you are using, so you can add the header with the bitmap.
Also what is the data format for the display (RGB 565, Etc.)?
Where is the kernel going to be stored and by what method are you going
to authenticate it?