Nothing Linux-based wants to boot - stuck at "calibrating apic timer". As I recall I've booted Linux before on an older Libreboot (437619c) without this issue.
KGPE-D16 (rev 1.03g, tried two different).
CPU: 6276 (one and two).
RAM: up to 8x4GB (HMT151R7BFR4C-H9 Registered ECC).
Boot device: SATA or USB.
A temporary fix is to use the nolapic kernel parameter, but this disables SMT (only 1 core!), and is unstable.
Seems to be related to GRUB thus booting entirely without GRUB should also fix this problem.
The problem is upstream, same issue (?) https://ticket.coreboot.org/issues/48.
TODO: Try if https://libreboot.org/release/stable/20160907/rom/seabios/ works, since no GRUB it should.