[flashrom] Trouble disabling write-protection on Chromebook

[David Hendricks]

Darn, still no luck then...

Well, I guess all that's left is to try finding a multimeter and seeing if
/WP is being held low somehow. Also, do you have an external programmer
such as a Bus Pirate?


On Fri, Dec 20, 2013 at 10:59 AM, <
BM-2cWKH3wgq8zXX9eHfba16oTc8b61ead4Yq at bitmessage.ch> wrote:

> > Can you try running "flashrom -p host --wp-disable -V" and pasting the
> > output on paste.flashrom.org?
> >
>
> Here it is:
> http://paste.flashrom.org/view.php?id=1851
>
> >  > If you have a voltmeter handy, you can also try measuring the voltage
> > on
> >
> >  > the /WP pin (pin 3). More details on pin configuration can be found in
> >> the
> >> > datasheet:
> >> >
> >>
> http://www.winbond-usa.com/hq/enu/ProductAndSales/ProductLines/FlashMemory/SerialFlash/W25Q32DW.htm
> >> >
> >>
> >> I don't have voltmeter; I'm sure I could locate one given enough time
> >> though. Do you have any other suggestions as to steps I might be
> >> overlooking here? Otherwise, what should I be looking for specifically
> >> in
> >> the Winbond data sheet?
> >>
> >
> > Unfortunately I don't have many ideas here... I've only seen this once
> and
> > it seemed to be a defective chip since I couldn't change the
> write-protect
> > status by removing the chip and using an external programmer. (This was
> on
> > a different machine, and not in a retail unit)
> >
> > The only reason for failure should be if there is anything bridging the
> > gap
> > between the copper pads around the write-protect screw hole, thereby
> > connecting /WP on the chip to ground. If you have a magnifying glass, can
> > you inspect just to make sure there is nothing connecting those pads?
>
> I took the Chromebook apart and cleaned the area around the write-protect
> screw hole using alcohol-dabbed q-tips a second time. Visual inspection
> did not reveal anything that appeared to be joining the two "halves" of
> the gold screw hole ring. Running "flashrom --wp-disable" as root gave me
> the same failure message as before, details in the paste.
>
> I executed "flashrom -p host --wp-range 0 0" and got this result:
>
> flashrom v0.9.4  : 4169bc8 : Sep 21 2013 02:17:24 UTC on Linux 3.4.0
> (armv7l), built with libpci 3.1.10, GCC 4.7.x-google 20130114
> (prerelease), little endian
> expected=0xe0, but actual=0xb8.
> FAILED
>
> Then, executing "flashrom -p host --wp-status" gave this result:
>
> flashrom v0.9.4  : 4169bc8 : Sep 21 2013 02:17:24 UTC on Linux 3.4.0
> (armv7l), built with libpci 3.1.10, GCC 4.7.x-google 20130114
> (prerelease), little endian
> WP: status: 0x00b8
> WP: status.srp0: 1
> WP: status.srp1: 0
> WP: write protect is enabled.
> WP: write protect range: start=0x00000000, len=0x00200000
>
>
>
>
>


-- 
David Hendricks (dhendrix)
Systems Software Engineer, Google Inc.
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