[REQUEST] Asus N56VZ RAM limit unlock

[chrono10]

Hi,

After experiencing a series of "adventures" with this laptop I went to try to upgrade its RAM from 16GB to 32GB.
Unfortunately that didn't work. It refuses to boot when using 2x16GB of RAM. Just a black screen. Even if I only try 1x16GB
The official asus page says the limit is total 16 GB of RAM.
But the oficial intel page for the CPU says it can support up to 32 GB of RAM.



I've opened the N56VZAS.217 file with UEFItool
I can see it's a `AMI Aptio capsule` and I found the following modules refering to memory:

Code:

24CCD374-3DF6-4181-86F6-E3C66920A145 --- UpdateMemoryRecord --- Full size: 1076h (4214)
3B42EF57-16D3-44CB-8632-9FDB06B41451 --- MemoryInit --- Full size: 26A42h (158274)

I've tried finding a similar asus laptop model that supported 2x16GB of RAM but haven't found a perfect match. So far I found two interesting ones.



The first is for K55VDAS411 which only supports 2x4GB-DDR3 (so half my laptop) and I can see:

Code:

24CCD374-3DF6-4181-86F6-E3C66920A145 --- UpdateMemoryRecord --- Full size: 1076h (4214)
3B42EF57-16D3-44CB-8632-9FDB06B41451 --- MemoryInit --- Full size: 26A42h (158274)

They have the exact same size! I've extracted the bins and did a hex comparision.
The UpdateMemoryRecord only differ on the PE header (timestamp field).
But MemoryInit is a lot different. maybe 75% of it.

Initially I was hoping to find a byte value with the max amount of memory allowed but that fantasy is now shattered.
Then I wondered that maybe replacing those modules/functions in the bios could solve it, assuming I find a perfect match (a bios for a 2x16GB laptop).

I've also installed IDA and efiXplorer plugin and opened `MemoryInit` PE body. But I can't conclude anything. The differences just keep on piling up.



The second bios of interest is for N752VXAS which supports 2x16GB... but this laptop use DDR4, while my laptop is DDR3L

Code:

24CCD374-3DF6-4181-86F6-E3C66920A145 --- UpdateMemoryRecord --- Full size: 120Ah (4618)
EEEE611D-F78F-4FB9-B868-55907F169280 --- PlatformInitPreMem --- Full size: 2110Eh (135438)

Which doesn't even have a matching `MemoryInit` module. But looking from the size maybe the `PlatformInitPreMem` is equivalent to it.


Assuming the hardware is the same, would copying the bios PE modules for memory init work? Or is this idea a pipe dream?
What about when dealing with different memory type? DDR3L vs DDR4? SODIMM vs DIMM?


Any comments or suggestions?

Thanks for any help.


PS: I just found out about TOLUD register in the BIOS. Could this be the cause of the problem and patching it would fix it?



My laptop bios:
https://dlcdnets.asus.com/pub/ASUS/nb/N5...odel=n56vz

Other bios I've tried to investigate:
https://dlcdnets.asus.com/pub/ASUS/nb/K5...odel=k55vd
https://dlcdnets.asus.com/pub/ASUS/nb/N7...del=n752vx

[falloutfit]

It would be great if my 5700g had access to 16GB of memory; however, it would be inefficient to use it for rendering in Blender, but it would free up read/write operations for smoother gameplay at higher settings. This unlock is a good bargain because the price of ddr4 ram has decreased, whereas 12 gigabytes of v-ram on a GPU would cost over £350.