Already being worked on, refer to https://review.coreboot.org/q/topic:haswell-nri

Great to see active work on this. Lets hope it get merged soon. There are many great features planed like for example:
"One of my future plans (automatic RAM overclocking) would try the highest possible frequency and, if training cannot succeed, slow down the MPLL to the next available frequency."

Current state of the meme magic (Haswell NRI)¶

Done¶

• Native non-raminit stuff (already submitted): needed for 9-series boards with Broadwell MRC.bin e.g. https://review.coreboot.org/68188
• Bare minimum memory initialisation (just enough meme magic to be able to boot): patch train up until https://review.coreboot.org/64198
• S3 suspend/resume and fast boot support: https://review.coreboot.org/81897
• Sense amplifier offset training: https://review.coreboot.org/81948

Implemented internally in the giant bowl of spaghetti, but in need to clean up the code before publishing¶

• 1D margin centering algorithms (used for various training steps)
• Setting non-training command rate (to 1N or 2N, we currently remain at 3T) and LCT (Late Command Training)
• 2D margin centering algorithms (used for various training steps)
• Power training (optimisation meme magic to reduce power consumption)
• TAT (Turnaround Training, a performance improvement)
• The raminit console (a half-arsed thing that allows playing around with settings over UART/usbdebug)

Not implemented or not working yet¶

• Broadwell support (I once got a Broadwell ULT system to boot without MRC, but I had to commit unspeakable horrors to the already messy codebase)
• Properly programming some registers about DIMM energy (doesn't seem to be required, but the logic to program these is horribly convoluted and I haven't felt like figuring out how it works)
• Automatic overclocking support (will require redesigning how the MPLL handling works, because it currently stinks)

TL;DR¶

• With what's currently submitted, choosing Haswell NRI in menuconfig WILL NOT BOOT. It says "NOT WORKING" in the prompt.
• Current top of tree (what you should use if you want to try Haswell NRI) is https://review.coreboot.org/81948
• With the aforementioned changes from Gerrit, booting should work. S3 resume should also work, but please test in advance.
• BACK UP YOUR STUFF! I will NOT be held responsible by any data losses arising from the use of the current state of Haswell NRI.
• Because not all training steps are ready yet, performance and power consumption are not optimal. Fix is to finish upstreaming them.
• Also, do NOT try to overclock the RAM under any circumstances. You will only make your system much more unstable for no reason.