how to flash ram SPD when it seems to be read-only?

Hi all,
___________________________________________________________________
EDIT: READ THIS POST ( I THINK I FIGURED IT OUT):
http://forum.notebookreview.com/showpost.php?p=5275126&postcount=4

also read these posts:
http://forum.notebookreview.com/showpost.php?p=5277863&postcount=15
http://forum.notebookreview.com/showpost.php?p=5278057&postcount=20
http://forum.notebookreview.com/showpost.php?p=5278138&postcount=21
___________________________________________________________________

So I am able to flash my kingston ram with spdtool. Works great.
Although for some reason spdtool does not recognise my SMbus driver unless I open setfsb and press getfsb. I know this is strange right? But it's not the problem.

The problem is that when I try my samsung 1gb 667mhz ram it seems to have a read only SPD.
When I flash it, during the verification it shows errors. The errors basicaly say that no values were changed. something like "blah blah blah verification failed".

I also have 2 sticks of 2gb 800mhz samsung ram which also seems to have a read-only SPD.

I would really like to be able to flash this ram (I want to see how far I can push my cpu but right now my ram is getting unstable), I am hopeing there is some way to do it. Maybe take off a resistor somewhere on the stick of ram or some other kind of mod I can make to let the SPD be flashed.

I am currenty looking for datasheets of SPD chips and also ram datasheets.
Hopeing to see something obvious that may help.
I haven't found a usefull datasheet yet.

If anyone needs it I can read off the numbers on the SPD chips (I believe I have spotted them on the ram, looks like they have 8 pins). I can also tell you anything else about the ram and I can post screenshot of the errors if needed.

thanks,
MH

 

bump. someone help me out please

 

Well i'll try to help (once I am able to send my memory for replacement/reflashing) by taking the heatsinks off and looking for differences.

But I can only send for replacement after the 7th (next month) and it will take 2-3 weeks to get them back.

 

OK I FIGURED IT OUT!!!!!!!!!!!!

The EEPROM does have write protection (pin7).

Please read this PDF:
http://jungle.at.tut.by/pdf/MemoryModuleSPD_Intro.pdf

look at table 1 on page 3.
It has the EEPROM pin description.

Here is the table:


Now it is time to modify that pin to dissable write protection so I can flash my ram

I believe I have to get pin WP tied to Vdd.

 

more technical documents can be found here:
http://jungle.at.tut.by/download.html

*just scroll down*

Its the official thaiphoon burner website.

 

Now I need to connecy pin 7 to Vdd(GND).
luckely the pin next to it (pin 8) is GND.

So it should be a very easy modification.
I would somehow have to dissconnect pin 7 from Vss. I will do some tests with a digital multimeter, hoping to find a resistor connected to pin 7.

Otherwise I would have to lift pin 7 from the ram.

I have attached a photo of my ram, I have pin7 and pin8 labled on the EEPROM.

 

So how do you plan to install a pull-down resistor when you get the pin disconnected?

Just asking, because connecting something directly to ground is not always a good thing.

 

pin 7 is an input pin. So I though if I lift it from the board it would get no signal.

Then I would connect pin 7 to pin 8 to set logic 0 to pin 7.

I'm a n00b at this sort of stuff, please tell me what part of it is wrong


Also I'm not sure if I have the pin numbering right can someone look at the following and tell me?



Edit: Do I have to use a resistor if I want to connect pin 7 to GND?

 

Ideally, you could put a 10K resistor between any pin and Vdd/Gnd. Tying two pins together should be okay as long as there is some kind of external pull up/down resistor connected between those two and Vdd/Gnd.

If there are weak internal resistors in the chip, and no stronger external resistors on the PCB, do NOT connect the pins together unless you have the spec sheet on the chip. One could default to pull up, another a pull down, and that would be...well...bad.

That circle indicates which pin is pin1, and yes your pin numbering looks correct.

ANSWER: Typically you do use pull down resistors to GND for I/O signals.

UPDATE: That pin 8 is a supply pin itself...it will NOT have a resistor acting as a pull-down. You need to run a 10K between the two pins. You should be able to solder a 0402 10K resistor between the two pins, but you'll need some soldering equipment and a microscope.

QUESTION: Can you see any PCB trace connecting to pin 7? You might be able to just etch that out with a razor blade (yes, I have done that) but you need to be careful with that. Do not try to snap the pin or anything, chances are you'll just break the EEPROM.

 

thanks for helping

one more dumb question, do I have to disconnect pin7 from Vss?

I mean could I just connect pin 7 to pin 8 with a 10K resistor and call it a day?

Or is this the right way to do it:
1. disconnect pin 7 from the board.
2. connect pin 7 to pin 8 with a 10K resistor

Also If this goes wrong is there a chance to kill my notebook?
I don't mind killing the ram ( already killed one stick by flashing wrong timmings onto it).