<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Dec 16, 2013 at 9:09 PM, <span dir="ltr"><<a href="mailto:BM-2cWKH3wgq8zXX9eHfba16oTc8b61ead4Yq@bitmessage.ch" target="_blank">BM-2cWKH3wgq8zXX9eHfba16oTc8b61ead4Yq@bitmessage.ch</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="im">>> As root in<br></div><div class="im">
>> developer mode, the output of flashrom -v is "flashrom v0.9.4 : 4169bc8<br>
>> ...". The first time I ran flashrom --wp-disable, I got a message saying<br>
>> the operation FAILED with error=1. At that point I took the board apart<br>
>> again and cleaned the write-protect screw hole with q-tips dipped in<br>
>> rubbing alcohol. When I reassembled the Chromebook and tried again with<br>
>> flashrom -V --wp-disable, the last few lines I receive are:<br>
>><br>
>> w25_set_srp0: old status: 0xb8<br>
>> w25_set_srp0: new status: 0xb8<br>
>> w25q_disable_writeprotect(): error=1.<br>
>> No -i argument is specified, set ignore_fmap.<br>
>> FAILED<br>
>> restore_power_management(): Power management enabled<br>
>><br>
>> As you can see, I can't seem to disable write protection on this chip.<br>
>> I'm<br>
>> running stock ChromeOS. Any idea what I might be doing wrong? Thanks in<br>
>> advance.<br>
><br>
><br>
> That's weird... Since you have the system taken apart already, can you try<br>
> disconnecting the battery while the machine is unplugged? I'd recommend<br>
> leaving it disconnected for a minute or so, the idea being to give the SPI<br>
> ROM enough time to fully discharge and reset.<br>
><br>
<br>
</div>Thanks for responding. I took your advice and disconnected the battery for<br>
several minutes. After reassembling the board and running flashrom<br>
--wp-disable again I am receiving the same message (FAILED). flashrom<br>
--wp-status says:<br>
<br>
WP: status: 0x00b8<br>
WP: status.srp0: 1<br>
WP: status.srp1: 0<br>
WP: write protect is enabled.<br>
WP: write protect range: start=0x00000000, len=0x00200000</blockquote><div><br></div><div>Hmmm, that looks correct for normal circumstances (with write-protection enabled). Flashrom *should* be able to clear bit 7 of SRP0, so the status should show up be 0x38 after running with --wp-disable.</div>
<div><br></div><div>Can you try running "flashrom -p host --wp-disable -V" and pasting the output on <a href="http://paste.flashrom.org">paste.flashrom.org</a>?</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<span style="color:rgb(80,0,80)">> If you have a voltmeter handy, you can also try measuring the voltage on</span></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="im">
> the /WP pin (pin 3). More details on pin configuration can be found in the<br>
> datasheet:<br>
> <a href="http://www.winbond-usa.com/hq/enu/ProductAndSales/ProductLines/FlashMemory/SerialFlash/W25Q32DW.htm" target="_blank">http://www.winbond-usa.com/hq/enu/ProductAndSales/ProductLines/FlashMemory/SerialFlash/W25Q32DW.htm</a><br>
><br>
<br>
</div>I don't have voltmeter; I'm sure I could locate one given enough time<br>
though. Do you have any other suggestions as to steps I might be<br>
overlooking here? Otherwise, what should I be looking for specifically in<br>
the Winbond data sheet?<br></blockquote><div><br></div><div>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)</div>
<div><br></div><div>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 assume that since you cleaned the area with rubbing alcohol that there is no residue from the sticker. I'm wondering if there is a tiny bit of copper (perhaps from a manufacturing defect) bridging the gap. If so, I'll ask one of our hardware engineers if it's safe to attempt severing it or if they have any better ideas.</div>
<div><br></div></div>-- <br>David Hendricks (dhendrix)<br>Systems Software Engineer, Google Inc.
</div></div>