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Re: RAM Chip Model/Part Numbers or Spec?


On Wed, 17 Aug 2011 14:52:06 +0200, Gilles Grandou <gilles@xxxxxxxxxxx> wrote:
Le 17/08/2011 14:35, Gordan Bobic a écrit :
On Wed, 17 Aug 2011 14:25:38 +0200, Marc Dietich <marvin24@xxxxxx> wrote:
Hi Gordan,

Has anyone got the model/part numbers for the Micron chips used in the AC100? Or the spec of the chips? I'm trying to find some larger capacity
chips that will be pin compatible.

I forgot the extact number (must have been something like
MT42L64M32D1KL-3 IT)
but you will find out when you open it ;-)

Note: there is a special code on the chips which you need to
translate to the
partnumber (http://www.micron.com/support/fbga.html).

But I wonder how you will solder a bga...

Thanks Marc. I was hoping it wasn't BGA, but these guys have re-chipped
non-DIY things for me before:

It'll probably cost a non-trivial fraction of a new AC100 (they are
cheap even by netbook standards nowdays), but it'll be worth it if it
leads to an ARM laptop with oodles of RAM. :)

I just have to figure out what chips are going to be compatible (need to find a Micron product list) and then find out what DIMMs have them on (I'm crossing my fingers that crucial.com support guys may be able to
tell me that).

My model is equiped with hynix chips, zoom on this picture:


Not quite enough pixels in the image to see the numbers, but never mind, I'll be opening mine up soon to fit a 1280x720 screen (again) anyway.

If you change chips you might have to upate register configurations
in arch/arm/mach-tegra/board-paz00-memory.c

Correct me if I'm wrong, but wouldn't that only be required if the new chips have slower timings? The size and GPU allocations are given as kernel boot parameters (mem/nvmem) so the extra memory should be specifiable there. Or at least that's the theory I'm working on.

However, I'm wondering how the bootstrap code would support new
unknown RAM chips if they are not strictly compatible (I think RAM
chips are described in the BCT partition, but its format is still

Well, that's just it - I'm hoping to find some RAM chips that are compatible (same width) and have timings that are at least as fast as what is currently fitted (this hopefully won't be an issue). Then the only thing to hope for is that the bootloader doesn't get confused by bigger RAM.