Booting OLPC OS 12.1 from USB sticks and SD cards

James Cameron quozl at
Tue May 22 08:17:30 EDT 2012

On Tue, May 22, 2012 at 08:01:48AM -0400, Martin Langhoff wrote:
> On Mon, May 21, 2012 at 5:39 PM, Sascha Silbe <silbe at> wrote:
> > If there's interest in diagnosing one or more of the failure modes I can
> > give details and maybe assist a bit in debugging (or preferably send you
> > the hardware), but it looks like a lot of work
> If an OFW hacker shows some interest, they'd say what to try. We've
> tweaked OFW USB and SD timings before to handle marginal or out of
> spec devices before :-/

Your wish is my command, etc.

I reviewed Sascha's report, and didn't find anything clearly caused by
Open Firmware.  Could I have more details please?  In particular:

> > two out of three USB SD card readers failing to work in OFW even
> > on XO-1.5. And that's for booting only; flashing from USB stick /
> > external SD card often fails somewhere in the middle with CRC
> > errors or SDHCI timeouts for media that works fine for booting."

Which USB SD card readers are to be supported?  I've only the one

Can samples of these devices be provided?

What filesystems are on these devices?

Have the filesystems passed consistency checks?

Booting requires a different pattern of access to flashing, so no
surprise that the symptom is different.

James Cameron

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