[coreboot - Support #626] (In Progress) Haswell Trad/T440p: Support for 16GB DDR3L modules with NRI?

Issue #626 has been updated by Angel Pons.

Subject changed from Haswell/T440p: Support for 16GB DDR3L modules with NRI? to Haswell Trad/T440p: Support for 16GB DDR3L modules with NRI?
Category set to chipset configuration
Status changed from New to In Progress
Assignee set to Angel Pons
Priority changed from Low to Normal
Affected hardware changed from T440p to Haswell Trad (e.g. T440p)

First of all, I feel I have to address the elephant in the room: are there any success reports of people using 16 GiB DIMMs on a Haswell Trad (traditional, i.e. not ULT) computer? For the record, I cannot magically work around hardware limitations.

Looking at the logs with the 16 GiB SO-DIMMs, they all have the following amounts of address bits:
```
    Row    addr bits  : 16
    Column addr bits  : 11
```
After investigating, looks like Haswell Trad only supports 10-bit column addresses, so 16 GiB (SO-)DIMMs won't work on the T440p (or any other Haswell Trad board). I believe the mangled graphical output (which I assume comes from the iGPU) happens because one of the bits in the column address isn't driven by the memory controller.

The margins themselves look fine, even though NRI currently only implements a few training steps. https://review.coreboot.org/89314 (more training steps) got merged yesterday, feel free to give it a try but I highly doubt it will help, although seeing the plots from the new training steps will help me confirm or deny whether the margins are okay.

That being said, looks like ULT supports 10-bit and 11-bit column addresses (12-bit column address support is yet to be confirmed). This would explain why the same SO-DIMMs work on the T450s (Broadwell ULT).

TL;DR the modules aren't supported on Haswell Trad, and I don't think I can do anything about it (other than adding a check, to handle the error properly instead of booting with unstable RAM).

----------------------------------------
Support #626: Haswell Trad/T440p: Support for 16GB DDR3L modules with NRI?
https://ticket.coreboot.org/issues/626#change-2229

* Author: Christian Schrötter
* Status: In Progress
* Priority: Normal
* Assignee: Angel Pons
* Category: chipset configuration
* Target version: none
* Start date: 2026-01-29
* Affected hardware: Haswell Trad (e.g. T440p)
----------------------------------------
There are rumors, that 16GB modules may be supported with NRI, even though the original BIOS nor the MRC blob support them in a T440p. I really wanted to test this myself, but unfortunately with limited success...

I have tested two different RAM modules over the last two months:
* ~~ZimaBlade - 16GB PC3L-10600S~~ (returned to seller)
* Micron MT16KTF2G64HZ-1G6A1 - 16GB PC3L-12800S

Both showed identical errors:
* The graphics output (via VGA) is mangled and unusable. Only a small "condensed" area is visible.
* EDK2 and memtest86+ start successfully (with the mentioned graphics issue), but memtest86+ crashes after a few seconds and causes a reset/reboot.
* GRUB2 loads successfully, but Debian (12/13) hangs at some point. Probably during kernel initialization.

The 16GB module from Micron starts up in other devices (Igel M340C + Lenovo T450s) without any problems and survives a memtest86+ over several hours. So it doesn't appear to be defective.

I then added various other 2/4/8 GB modules in addition to the 16GB module. Funnily enough, this changes the graphics output! Now every second line (each consisting of a few pixels in height) is displayed correctly. Unfortunately, this does not change the fact, that memtets86+ crashes and Debian can't boot.

I purchased a USB dongle (with a FT232H chip) specifically to read all Coreboot debug logs and have attached these along with my build configuration for v25.12!

I would like to know whether 16GB modules are really not supported in a T440p with NRI, or whether this could be a bug? I am happy to execute further tests or flash specific commits.


---Files--------------------------------
defconfig (650 Bytes)
1769676506-2512-nri-2gb.log (51.8 KB)
1769677242-2512-nri-16gb-bottom.log (137 KB)
1769677400-2512-nri-16gb-top.log (85.4 KB)
1769677514-2512-nri-16gb+2gb.log (152 KB)
1769677649-2512-nri-16gb.log (85.4 KB)


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