This is oreboot booting on an AMD Rome CRB. The logging is copious, so be patient.
You might want to start about 40 seconds in and run it at 10x …
We start in oreboot, then load and boot Linux, then start user mode.
The final % you see is a u-root based initramfs running the Elvish shell. You can see we type a few u-root commands (for more, see github.com/u-root/u-root for more on u-root).