I am trying to display a splash screen when I boot my X220; after
failing for the better part of a day I'm not sure if this is supported
in Libreboot so I figured I'd ask. I have tried:

* Setting the framebuffer to my native resolution (1366x768)
* Setting the framebuffer to a "compatible" resolution (1024x768)
* Using a native-resolution image
* Using a compatible-resolution image
* Using an image whose dimensions are divisible by 16 (1360x768)

And all relevant combinations thereof.
I have made sure my images conform to the SeaBIOS JPEG decoder's
quirks, so I know it's not that either. Every time I try to boot with
the graphical splash enabled I never seem to successfully POST; I have
a black screen and the laptop doesn't respond to input, I have to
manually flash a new ROM.

Is the graphical splash screen supposed to be functional in Libreboot
or is it Coreboot-only? I am using the latest release, 20240126.

-Jeremy