Thank you all for your support,
My x201 is a Nehalem architecture, not IVB (Ivy Bidge I suppose)

On 11/23/2016 02:40 AM, Charlotte Plusplus wrote:

On Tue, Nov 22, 2016 at 4:28 PM, Zoran Stojsavljevic <zoran.stojsavljevic@gmail.com> wrote:
If MCU is later, could you, please, explain how you did this in IVB Coreboot code (since this might be beneficial to Federico's attempts)?

Edit devicetree.cb and set:

 register "max_mem_clock_mhz" = "666"
I've looked inside `src/mainboard/lenovo/x201/devicetree.cb` but the option "max_mem_clock_mhz" is missing,
while it is present in other sandy bridge mainboards.
So I think the actual `raminit.c` of nehalem does not allow choosing a fixed frequency for RAM.

Here I understood that you tried to compare IVB raminit.c source code with MRC algorithm, embedded in BIOS itself. And I have here one ignorant question: what is the difference between IVB (I assumed in this case SNB (tock), since I could not find IVB (tick) in rc/northbridge/intel/) raminit.c source code and MRC from IVB BIOS (there MUST be some difference, it is obvious, doesn't it)?

I suppose there is one. I don't know. I want to investigate. I will certainly try again by adding the patches suggested by Kyosti. As soon as I can get the MRC blob to work, I can make some better guesses about what is going wrong (I tried so many various things already) by having some reference points.
About trying with MRC blob RAM init, sadly the source file `raminit_mrc.c` present for SNB is absent from `src/northbridge/intel/nehalem`
So I think MRC blob init has not been coded/is not supported in nehalem :(
This is confirmed by this wiki page: https://www.coreboot.org/Intel_Native_Raminit

So the options of fixing frequency or using MRC are not feasible on nehalem at the moment.
I will try to check the RAM settings running the Lenovo bios and see if i can add the code for "max_mem_clock_mhz"
Unfortunately I won't be able to flash coreboot until friday because my laptop needs an external power supply for the flash chip
and I will borrow it on friday.

Thanks again,
Federico