Help for mod on mini2440. Upgrade SDRAM to 128MB

Hello guys,
some time ago I bought this mini2440 dev kit but unfortunately the SDRAM
size was not suitable for my application and to solve this I decided to
upgrade the memory. So, I bought an old PC133 512MB memory card wich has 8
memory banks, so each bank has 64MB of space. Using 2 of then I will stay
with 128MB of SDRAM and that size may be good for my application. BUT, its
not that simple, its not just de-soldering one chip and putting on the
place of the other. Reading the datasheet of the microcontroller I saw that
its necessary to use the line ADDR26 of the micro to control the BANK ADDR
of the memory. The problem is I don´t know wich trail corresponds to the
ADDR26 of the micro, worst, this trail could not even exist, and then I
would need to take the micro off the board to fisically solder a wire at
this specific point. Being so, i started to search for the layout diagram,
or circuit diagram, that shows the specific details of the trails and
layers of the board but I cant find that kind of information. So, im asking
here if someone has this layouts and diagrams if could send it to me.
Thanks very much.
Lucas.

As far as I am aware no one has ever seen the PCB layout of the board. 
This information is not normally released to the public.

Also, the PCB probably has 6 or more layers!  

Someone did try replacing the SDRAM with the same part as used on the
bigger boards.  I have been trained in basic SMD repair and would not
attempt this feat myself.

I suggest to just buy a board with a bigger SDRAM on it.

Dave

Hello, Dave.
Thanks for you advise but my curiosity to see the whole thing working with
an upgraded memory was bigger enought to make me take off the
microcontroller.
The good news is that I found the ADDR26 line and now its easier to upgrade
the memory. But as always when we have good news there are some bad news
too, the bad news is that to solder the micro back to the board is not as
simple as taking it off. I'll need to wipe off some old solder remaining on
the board and reball the microcontroller. Not that hard, actually but not
that simple aswell.
Thanks,
Lucas.

Yikes . . . BGA replacement at home.  Now there's a man who likes a REAL
challenge!

Good luck.

Or a man who likes a dead board? :)

I've seen one can buy bga reballing solder... i think its little balls
which you place on the board, place component and into the oven!

So maybe its not that far fetched.... how the heck do you remove the part?
Also using a reflow oven or hot air?

I must admit... BGA is about the only thing I'm still afraid of doing
myself.

Dave, I´m using some professional tools like hot air station, 10x
microscope, very small tweezers, flux paste, liquid flux, etc. Ill receive
the bga ball today, so tomorrow I can post more infos.
Thanks.

Andre,
I used a hot air station to remove. Removing it is very simples, the
problem is that when you remove it, the remaining solder on the board and
on the BGA component is useless and then you need to reball the whole
thing.

Let us know how you progress... would be nice to know if the ram can be
upgraded... i would imagine you'd need to make some changes to the bios to
make it compatible with 128mb, but that's also been done before on other
platforms.

I upgraded my router (Linksys WRT54GL)'s ram some time back... router got
fried by lightening since, but it worked and required some software changes
also to get it working... this was following instructions somewhere for
openwrt or dd-wrt - cant remember which one.

Is there any progress on RAM upgrade process? I'm afraid this is not an
"plug and play" process, I think the bootloader needs some changes to
recognize new RAM size.

It seems the BIG PROJECT was halted. Sad news. I also want to upgrade RAM
for the board, but i don't know how. However, could we use SD_card act as
RAM???