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Re: [Libreboot] flashing the c201

From: Rendov Norra
Subject: Re: [Libreboot] flashing the c201
Date: Sun, 11 Sep 2016 16:00:47 -0700

For the records:

Well, I picked up a buspirate and set it up and managed to get it to flash.
Not sure what was wrong with my pi setup. Faulty hardware? Faulty drivers?

In any case, thanks for the help.

On Tuesday, August 16, 2016, Rendov Norra <address@hidden> wrote:

> This is a continuation of an email I sent paulk, since he suggested I post
> here as well.
> I checked all of his suggestions except maybe if all the required pins are
> getting 3.3v. I'm not entirely clear on how to measure that. I get ~2v when
> measuring from the power source to the pin, and the ground connected.
> Measuring straight from the power to ground gives me 3.3v.
> The power, hold, and wp pins are all bridged and receiving power from
> {pin1,pin17} of the rpi, which is documented to provide 3.3v.
> I'm wiring it according to the following documents (pdf warning):
> 100413_wo_automotive.pdf
> Raspberry-Pi
> ---------- Forwarded message ----------
> From: *Paul Kocialkowski* <address@hidden>
> Date: Monday, August 8, 2016
> Subject: On flashing the c201
> To: Rendov Norra <address@hidden>
> Hi,
> Le dimanche 07 août 2016 à 19:45 -0400, Rendov Norra a écrit :
> > This is a bit of a longshot, but I'm pretty desperate.
> >
> > I managed to make chromeos boot on the c201, and external device boot is
> off,
> > and the chromebook recovery images fail after ~5 minutes, so as far as I
> can
> > tell, using internal spi to flash is out of the question. I've resorted
> to
> > hardware flashing, but I can't get it (RasPi 3) talking to the chip. And
> it
> > boots into the firmware (and into recovery), so I know I haven't managed
> to
> > fry it.. At least I hope.
> >
> > I've set the pins according to multiple sources, and re-checked them God
> knows
> > how many times. I've tried different configurations of powering the hold
> and
> > write protect pins. I've checked continuity between the RPi and the legs
> of
> > the chip too many times. The write protect screw is out. I've even tried
> > having it sit in the developer/recovery screens and use the power
> supplied by
> > the board. I've tried using upstream Flashrom, and I've tried using
> google's
> > Flashrom. No matter what I do, it returns "Unknown SPI chip".
> >
> > I figured if anyone knew anything about this, it'd be you. Thanks for
> your
> > time.
> Please consider posting this to the Libreboot mailing list as well. This
> way,
> more people can help you and answer your inquiry while others can benefit
> from
> the question and its answers as well.
> Some notes and suggestion that may help you:
> * Make sure you've followed
>   and especially "Installing Libreboot externally, with a SPI flash
> programmer"
> * Check that the VDD, #WP and #HOLD of the chip are +3.3V during activity
> * Make sure that you're not using 1.8V logic, the chip seems to accept
> 3.3V only
> * Make sure you've disconnected the device's battery
> * Make sure you've disconnected any source of power
> * Maybe try with the battery connected, just in case
> Note that I'll be providing a recovery SPI flash image and rootfs with
> Debian
> that should allow recovering from these kinds of situations. Of course,
> your
> device is not irremediably bricked.
> Cheers,
> --
> Paul Kocialkowski, developer of low-level free software for embedded
> devices
> Website:
> Coding blog:
> Git repositories:

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