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Dear Nico,<br>
<br>
><br>
> It might be easier to help if we knew your Laptop model. Also, please<br>
> provide a full log of the failing flashrom run with the -V switch, you<br>
> can specify a log file with -o.<br>
><br>
<br>
Right now I'm away from that laptop and cant remember its model<br>
(or provide a flashrom log) However I remember the most important thing:<br>
the model of BIOS SPI flash chip is EON EN25QH32 which is supported by <br>
flashrom since version 0.9.6 . I got a latest datasheet at official EON website<br>
( here it is - http://www.eonssi.com/upfile/p2013114174725.pdf )<br>
<br>
><br>
> Please further define "without problems". Did you try several reads and<br>
> compared the contents?<br>
><br>
<br>
Yes I tried several reads and the contents of flash chip are always the same.<br>
Moreover, I was able to successfully write 00s and FFs for a few times, and<br>
right now the contents of SPI flash chip: 00's - first 1MB , FF's - last 3MB<br>
<br>
><br>
> By guessing two possible issues come in mind: 1. Your programmer doesn't provide<br>
> enough power for erasure. 2. The write protection pin of your flash chip is asserted.<br>
><br>
<br>
Because I was able to write at least some stuff, I believe that your 1st theory is true:<br>
maybe a part of current that should be going to flash chip for a successfull write,<br>
is powering a half of the surrounding circuit instead...<br>
<br>
><br>
> I'd try with the AC adapter. In that case Vcc must _not_ be connected to<br>
> your programmer. GND, OTOH, has to stay connected.<br>
><br>
> Not forbidden. It's sometimes even encouraged because there are boards<br>
> where the Vcc pin of the flash chip is directly connected to other<br>
> chips, which would draw down the power from the programmer.<br>
><br>
<br>
Thank you very much for advice, Nico! As soon as I get back to equipment I am<br>
going to disconnect a Vcc pin from a programmer to avoid the overvoltage<br>
(just checked the datasheet above and Vcc is the 8th leg of that flash chip)<br>
Hopefully it will be powered good enough by the AC adapter ;-)<br>
<br>
Just not sure what to do with a CMOS battery, too afraid to connect it back<br>
together with AC adapter - if there would be overvoltage I am screwed...<br>
<br>
><br>
>><br>
>> Or its better to try to power Vcc of flash chip from "USB to TTL"<br>
>> adapter - which has this 3V3 (3.3V) voltage pin?<br>
>><br>
><br>
> It really depends on your machine.<br>
><br>
<br>
EN25QH32 datasheet tells that this flash chip supports between 2.7V and 3.6V,<br>
3.3V seems OK and I would probably try taking it to Vcc from "USB to TTL adapter"<br>
if the solution with a laptop's AC adapter will not work...<br>
<br>
AC adapter would also powering EC controller, so what if EC will setup a write protect?<br>
<br>
Best wishes,<br>
Robert Brown<br>
<br>
<-----Original Message-----> <br>
>From: Nico Huber [nico.h at gmx.de]<br>
>Subject: Re: [flashrom] SOIC8 test clip - cant write to BIOS SPI flash chip<br>
><br>
<br>
><br>
>On 17.10.2015 02:07, Robert Brown wrote:<br>
>> But here is a problem: I could read a dump from this BIOS chip without<br>
>> problems, however<br>
><br>
><br>
>> it fails when I am trying to write - so the contents of BIOS flash chip<br>
>> are remaining unchanged.<br>
>Log please. By guessing two possible issues come in mind: 1. Your pro-<br>
>grammer doesn't provide enough power for erasure. 2. The write protec-<br>
>tion pin of your flash chip is asserted.<br>
><br>
>> Should I connect to motherboard a laptop's power battery, or small CMOS<br>
>> battery, or AC adapter of laptop,<br>
>I'd try with the AC adapter. In that case Vcc must _not_ be connected to<br>
>your programmer. GND, OTOH, has to stay connected.<br>
><br>
>> so that this Vcc pin would be powered by them, or it is forbidden to do<br>
>> it while using SPI programmer in the same time?<br>
>Not forbidden. It's sometimes even encouraged because there are boards<br>
>where the Vcc pin of the flash chip is directly connected to other<br>
>chips, which would draw down the power from the programmer.<br>
><br>
>> Or its better to try to power Vcc of flash chip from "USB to TTL"<br>
>> adapter - which has this 3V3 (3.3V) voltage pin?<br>
>It really depends on your machine.<br>
><br>
>Nico<br>
>.<br>
>
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