[Sugar-devel] USB stick advice

[Sean DALY]

OSX's FreeBSD has dd but no syslinux :-(


On Tue, Apr 14, 2009 at 10:16 AM, Tomeu Vizoso <tomeu at sugarlabs.org> wrote:
> [cc'ing fedora-olpc because we are using unmodified fedora tools]
>
> On Mon, Apr 13, 2009 at 23:33, Walter Bender <walter.bender at gmail.com> wrote:
>> Thanks. This is all helpful. I wonder what the Fedora USB Creator does
>> when it runs under Windows?
>
> AFAIK, what Mitch says is what we currently do when using both
> livecd-iso-to-disk.sh and the Fedora Live USB creator.
>
> For flashing a big number of sticks with a port replicator, we could
> first use livecd-iso-to-disk.sh to copy the partition files to one
> stick and set the bootable flag, then use dd to read into an image and
> then dd again to write it to the rest of the sticks, provided they are
> actually identical inside.
>
> Regards,
>
> Tomeu
>
>> -walter
>>
>> On Mon, Apr 13, 2009 at 3:53 PM, Mitch Bradley <wmb at laptop.org> wrote:
>>> My first order recommendation is "don't use dd to blast an image over the
>>> existing partition map".
>>>
>>> The problem with doing so is that it wrecks the factory partition layout.  I
>>> strongly suspect that said factory layout is, on many sticks, optimized for
>>> the characteristics of the stick's internal firmware and the hardware block
>>> sizes of the NAND Flash chips.
>>>
>>> Unfortunately, the alternative is rather more complicated procedurally than
>>> "dd and pray".  But given the indifferent results from dd&pray, I think it
>>> may be worthwhile to go for a more elaborate procedure.
>>>
>>> Here is an outline of what I think really should be done:
>>>
>>> a) Ensure that your filesystem image is somewhat smaller than 1G (or 2G or
>>> whatever your base size) so it will fit on "all" 1G devices.
>>>
>>> b) The image is just the partition contents, excluding the partition block
>>> and master boot record.
>>>
>>> c) The installation procedure involves
>>>
>>> c1) Editing (not replacing) the existing partition map, setting the first
>>> partition's "boot flag" byte and changing its filesystem type to ext2 or
>>> whatever.  (Ideally it would better not to change the filesystem type,
>>> instead sticking with the factory FAT partition, but I understand what a
>>> hard nut that is to swallow for Linux enthusiasts.)
>>>
>>> c2) Copying the image into the partition
>>>
>>> c3) Installing your bootloader using an installation program instead of dd,
>>> thus replacing the first sector's Master Boot Record and doing whatever else
>>> is necessary to complete the bootloader's installation.  I have had the best
>>> results with syslinux.
>>>
>>> There is, of course, a chicken-and-egg problem of how do you run the
>>> bootloader's installer.  On the other hand, you have the same problem with
>>> "dd" - in principle, on any machine that can run "dd", you can also run
>>> syslinux.
>>>
>>> If you want to talk more about this issue, please feel free to keep the
>>> conversation going.  It is a topic that has been much on mind recently.
>>>
>>> Mitch
>>>
>>>
>>>
>>> Walter Bender wrote:
>>>>
>>>> I was wondering if you have any words of wisdom to share with us re
>>>> USB stick compatibility, given your experience with the XO. There
>>>> seems to be a lot of variability in terms of which sticks boot which
>>>> machines in our Sugar-on-a-Stick experiments, e.g., using the same
>>>> machine (a Classmate running XP) to burn the same image (the Beta SoaS
>>>> iso) onto USB storage media from three different vendors, I cannot
>>>> predict which one(s) will be bootable on any particular piece of
>>>> hardware. Is there any deterministic way to proceed, or is trail and
>>>> error our only recourse?
>>>>
>>>> thanks.
>>>>
>>>> -walter
>>>>
>>>>
>>>
>>
>>
>>
>> --
>> Walter Bender
>> Sugar Labs
>> http://www.sugarlabs.org
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>>
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