ROM Hack Micro soldering NAND chip or NAND dump (recovering lost data)

[mistermcsenpai]

About 6 years ago my DSi XL got wet and stopped working ever since. When I try to turn it on the orange light flashes, and that's about it. I opened up the board and I noticed there was a bit of corrosion around quite a few parts. The DSi holds many important and sentiment pictures from my early childhood that I would like to recover from the camera roll. Since the board is pretty toast I thought the only way was to go through the NAND chip since its still in one piece.

So firstly, the easy way. Is there anyway to somehow force a NAND dump onto an SD card despite the DSi not having any homebrew installed and nearly dead? I say nearly dead since the orange light flashes which suggest there is still a very tiny amount of life left in it.

The second possible way would be somehow unsoldering the NAND chip* from my current board and put it on a new board. (*I've heard the NAND must also have the same CPU, so that may also need to be changed). Does anyone know if it is possible to do this for a slight amateur? I've done a bit of soldering and repaired quite a lot of tech, but have never done anything close to micro soldering. I noticed there are no visible contact points for the NAND chip so I assume they are under the chip which makes this 10x harder.

I would imagine I owuld need solder balls and those stencil things. Does anybody know if they even make stencil's for DSi nand chips?

This third possible way is even more absurd but may turn out to be easier than the second method for an amateur. So after removing the NAND chip, could I somehow manually wire up each point to a new donor boards respective contact point? This might be easier since I can actually see what I'm connecting too, since placing the NAND back onto the board seems quite tricky since I can't see any contact points.

If anyone has any information regarding my data recovery, that would be very much appreciated. Thanks

 

[FAST6191]

You will usually use hot air or infrared (IR being the preferred way for most) to do solder ball stuff, which is known as ball grid array aka BGA. Not especially difficult if you know the tools you are using but a considerable investment in tooling if you don't have it already, and you only get a few shots (too many thermal cycles of chips and they start being a bit eh).
General workflow is you desolder what you want desoldering, clean it up, get a stencil (usually made of a material that does not see solder stick to it), carefully place a solder ball on all the relevant pads (or chuck a bunch down and poke them around), flow the balls onto the pads on the bottom of the chip, prewarm the new board (somewhat optional but makes life a whole lot easier/things a lot more reliable), cover non warmed parts of the board with foil or something to reflect/stop heat, do the particular cycles you need to melt solder (if you used nice wonderful leaded solder it will be different than using some nasty lead free horror) and then reassemble.

You could run what would be known as bond wires between the chip and a pad. Very tedious and risks cross talk issues. Normally only one or two things are replaced here to make up for a bad contact (flexing board or something).

I imagine the CPU will have to come along for the ride (it is normal policy for any kind of secure device to read the CPU to make sure it is on the right board), or at least it will be the far easier method.


What might be easier is cleaning up the board, or at least cleaning it up enough that it will boot (possibly after putting the motherboard into a spare DSi) for long enough to get things off it. This you can possibly do with more minimal tooling (maybe an iron, maybe an iron and a cheap hot air station). Clean up corrosion, if somehow a component is blown (the orange light going off is often a fuse indicator) then replace that (and if you have a donor board then you hopefully have some nice reference values and possibly donor parts if some are not going to be basic components.