Friday, 15 May 2009

○ Dead Nvidia 8600M GT GPU VBIOS Flash Needed?

Hello, so you have a dead NVIDIA 8600M GT ? Well, were you the culprit? In this article i will try to explain most of the details involved when trying to save your dead gpu, but i can't be hold responsible for any damage this may cause, so read wisely.

First of all, before the card died, did you notice strange artifacts on dark areas of the screen? Like when you are seeing a picture the blacks are drawned with yellow strange artifacts without the card even being overclocked and apparently running on normal temperatures? And suddenly after a few days all your screen got corrupted like the image is out of sync? Stripped colores lines all over the lcd, and garbled characters in DOS mode and even during POST? If so, the diagnose for your dead gpu card is: Bad memory modules, unrepairable by software means!

One of the things people try to do in this situation is to try to save the gpu card by flashing the VBIOS with a good ROM image, but it is a waste of time in fact. NO, using Nibitor to try and reduce the core and memory bootclock speeds will NOT help. If it's under warranty send it to repair, gpu card or hardware repair, i know how it can be frustrating..

On the other hand, if you got here because you were trying to overclock your card and you changed sensitive information like timings ( the fastest way to make your card not boot again) or voltage settings and now the display won't turn on, one of these two things apply: POST's correctly or it doesn't POST.

I will start with the "does POST" scenerio, in this situation to fix your dead gpu you may try to use NVFlash to reflash the VBIOS using a Bootable USB PEN editing autoexec.bat file and adding the nvflash instructions there ( Read nvflash.txt for usage instructions ).

If you're at the "does not POST scenerio", things are much more serious. I have heard people saying that you can try to prepare the bootable USB pen as you did if you didn't have POST problems and leave the computer all night to see if he would bypass POST. Personally i don't like this because if the computer doesn't POST after 30 minutes max, i see no reason why he would POST after an hour or more, but you can try it. Anyway, there might be a more straightforward solution, that it is to go with the hardware route. altough not easier, but given my knowledge on this i can only give you some tips. Nvflash document describes the -j option you can use to force flashing the gpu when the STRAP_SUB_VENDOR pin is grounded. Now where is this PIN? Apparently it can be named several things, depending on the vendor. This is a picture of my Nvidia 8600m GT 512 DDR2 card, MXM-II type slot.

The chip on the top left side is the chip where the VBIOS is

The chip is an SST25VF512 in this case, it has 8 legs total, 4 legs on each side . You can download the datasheet and see on page 3 a detailed description on what each PIN does and how it relates to some possible operations.

One of them is the CE# Chip enable, this PIN when grounded to Vss, disables the chip security i think, altough i haven't read the datasheet with much attention, but the STRAP_SUB_VENDOR sure is not described there or any other place i searched. To my knowledge however it seems to me that this PIN is the same as the CE ( chip enable ) PIN and sometimes, for other chips it might be the CS ( chip select ) PIN. The procedure however should be similar, connect to ground Vss. Given the very small size of the chip one effective way to connect both is to use a thin tweezer, but caution is advised, as you may understand you can ruin other components if you are not carefull.

Once done and the computer is turned on, if you have beeps on your computer it should beep to tell you something like GPU bypassed. If you dont have beeps i guess you just have to see if the VBIOS flashes with the USB boot disk. The main reason why you need to use the strap subvendor pin is because nvflash can't detect the card anymore. I did a test with my dead gpu and got the following output:

Version 5.72

Command: flash

ERROR: No NVIDIA display adapters found
Exit Code: 2

When i tried the other nvflash options to try to bypass everything i could i got:

Version 5.72

Command: flash

ERROR: EEPROM override not allowed for write operations
Exit Code: 2

This is were i decided to just arranje an RMA.

Finally, i would like to add that it seems that several batches of NVIDIA 8600M GT were built and released with design flaws, leading several of these notebook cards suddenly get ruined or dying near the end of the usual warranty period, even if you are not a gamer and never overclocked your card to begin with. I can't atest to the veracity of this design flaw, all i can say is that it happened to me, thus why i decided to write this. I never got to try the tweezer method tough, i arranged a RMA for it as it still was under warranty.

Hope this can be usefull somehow, thanks for reading and good luck reviving your card, if it's already out of warranty period you can try the tweezer method in case you have flashed a bad VBIOS, otherwise if the problem is corrupted memory chip modules, the only option is to replace them in a specialized lab ( probably cheaper than buying a new card) but nothing guarantees it won't happen again.

Here is a picture of the back of a Nvidia 8600M GT 512MB DDR2 is anyone needs it.

For further info on reviving dead GPU cards trough hard flashing an MXM card's BIOS you can check

Taken from:


  1. Hi I did a wrong bios flash and now I am trying the tweezer method. By the way I still can not see my acer 7520g pass post...screen is always black. (pins shortcutted are 1 and 4)
    There is no activity from the usb pen drive attached...
    Is something else I need to know? thanks

  2. Hello, sorry for not answering you earlier. The tweezer method is usefull to allow the computer to bypass the GPU on POST, did you heard any beeps? Did you check the datasheet for your specific acer card? Pins may differ. Did you try the usb pen in another computer (remarking the nvflash command just to see if pen is bootable?) If your USB pen is bootable and had no activity when everything was set then, cleary you were not past post. Be sure to check that autoexec.bat is properly set and perform the tweezer method once more. If you try to completely remove your GPU card from the notebook (in case its removable) you will see that the notebook will POST, tweezer method principal is the same, shortcuting to "disconnect" it from the notebook, altough it's already there. If your card is MXM II DO NOT try to insert the card into the notebook, while it is connected prior to POST. if you read MXM II specification you will see that MXM II is not hot plug compatible, meaning that it won't be prepared to protect your card. If you have tried all the above options, and still no go, follow the next best advice: Save time, and buy a new one, or used one. Good luck

  3. Hi Miguel, i did revival my 9600m gt previously flashed with erroneus bios image.
    Maybe you will be interested in the story and in pictures I did during such operation.
    What I did was to desolder the bios eeprom and than hard flashed it with my eeprom programmer by using a SIP 8pin adaptor.
    If you would like I can send you some text describing the full procedure and should be usefull for those people who tried to use the "shortcutting pins method" and it did not work.

  4. In reply to 21 Feb Post:

    That would be kindly apprecciated. That must have been a very precise and carefull task, desolder a tiny little eeprom witouth messing around is a tough task. Was the programming kit/software accessible? We would love to know about the details. Thanks

  5. hi Miguel, surelly tomorrow I will start writing the article as better I will...then I will send you both the text and pictures...hope this will save some poor souls that have tried to bypass their notebooks mxm limitations by flashing some bios images they should not :)
    ...sure :P the task was not easy...the only person who assisted me in such a operation was my wife who at last sayd - when you will stop playing with such crappy tools and start instead doing something usefull in home? :)

  6. :) I should forward this question to my wife...maybe I should not :)

  7. Thank you for your contribution, it's now posted at

  8. Hi, nice tutorial
    Maybe can you help me to find the chip and pins on my NV quadro fx 770m? I damaged my vbios....