I have been looking at trying to port coreboot to my HP zBook 15 G2. Everything is seemingly fine, I can get an image built as this machine is similar to the Lenovo t440p. Unfortunately I have yet to have a successful startup. There are a few differences in the machine which include having a dedicated Nvidia GPU, which i have loaded the video bios file for based on how things were done for SpookySkeletons' 8770w build at https://github.com/SpookySkeletons/Coreboot_8770w
The only thing I can think of would be the Embedded Controller. Unfortunately there isnt a lot of documentation on how the EC could cause these problems nor are there any hints towards how to potentially integrate them into the build. I have found that the EC is an MEC1322 which is a part of the chrome-ec project and was wondering if there may be an easy way to do this integration to further test.
Thanks