[Sugar-devel] USB stick advice

[Walter Bender]

Thanks. This is all helpful. I wonder what the Fedora USB Creator does
when it runs under Windows?

-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