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Date: Thu, 5 Mar 2009 17:34:55 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Raw device access to an SD card
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On Mar  5 17:49, Hannu Koivisto wrote:
> Greetings,
> 
> The goal is to create a bootable Linux installation on an SD card
> by writing an existing image using dd in Cygwin.  The card is
> inserted to an SD card slot of a laptop and apparently appears as
> \\.\physicaldrive2 to the OS.
> 
> Now, "dd if=\\\\.\\physicaldrive2" reads something (hopefully from
> that card, hard to say for sure) but an attempt to write with "dd
> if=image of=\\\\.\\physicaldrive2" fails with "Invalid argument"
> error.  Should this work?

Not really.

Don't use Windows device names.  You can find the mappings from POSIX
device names to Windows device names here:

  http://cygwin.com/1.7/cygwin-ug-net/using-specialnames.html#pathnames-posixdevices

In your case that would be /dev/sdc.  But that probably won't work.
I don't remember the exact details, but you shoudl rather access
the first partition on the device, rather than the entire device.
like this:

  /dev/sdc1

> first?  I tried "mount -f -b //./physicaldrive2 /dev/foo" as
> suggested by someone but according to the Cygwin user's guide that
> is deprecated and besides, /dev/foo behaved just like
> \\\\.\\physicaldrive2 directly.  FWIW, I tried to find if the card

Yep.

> device gets mapped to some /dev/sd? but that didn't seem to be the
> case.  Only /dev/sda was available (hard drive).  Is it possible to
> list that kind of mappings somehow?

cat /proc/partitions


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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