an out-of-tree change is not needed anymore. coreboot upstream includes the
latest microcode updates we need.

the bootsplash image is added to the build.

see #21

this simplifies the microcode pull-in

We rebased commit ([WIP] 3rdparty/blobs: Bump for new microcode update for
Intel model 306ax) to the current coreboot master state fb758d420b and
update our build scripts.

We run oldconfig on our config and update it.

shamelessly taken from https://github.com/Thrilleratplay/coreboot-builder-scripts

thanks a lot!