From what I recall, the last coreboot master I tried resulted in crashes without your patch.
If it's so, then the HT patch is not to blame... But we'll see after your tests.
I intend to run following tests with the latest coreboot master (I'll note the commit hash and use the same commit for all of my tests) and SeaBIOS as payload (blobs will be extracted from the Lenovo OEM BIOS v2.81):
- fully blob'ed (vgabios, ifd, me, gbe)
- libgfxinit instead of vgabios
- fully blob'ed with the me shrinked
- libgfxinit instead of vgabios with the me shrinked
I personally don't think that libgfxinit instead of vgabios or vice versa will make any difference in this case. I'd recommend to test native raminit vs mrc.bin instead.
I'm unsure on how to provide the µCode patches, i.e. integrate them in coreboot or have them patched by Linux.
If you mean microcode updates, then there's an option in coreboot's config (and you also need to enable use of binary-only repository in the General section).