i believe that raminit isnt done via a blob anymore. you might as well read the official docs.
coreboot isnt even in the main tree yet! you have to use libreboot unless if you want to hunt down mate kukri's branch and go off that. you also have to use deguard to disable intel boot guard. It is more work than ivy bridge, which is why I use libreboot; its all done for you, its reliable and updates are done by someone else (you dont have to update your own payload yourself and recompile and retinker etc).