Booting OLPC OS 12.1 from USB sticks and SD cards

[Sascha Silbe]

Martin Langhoff <martin.langhoff at gmail.com> writes:

> I see 100% success on XO-1.5 :-)

Yes, in my tests it has been working best. All devices that refused to
work with XO-1.5 don't work with XO-1 and XO-1.75 either. But that's
still 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.

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 reliably identifying
flash media (and consumer hardware in general) were possible for end
users a list of known-working hardware would be a better approach.

After spending the better part of another day testing the individual
devices on the various XOs (knowing what software quirks to expect) I
now have a list of known-working and known-problematic card readers and
flash media I own so I can use the known-good ones for testing.


> Jokes aside, I don't think that booting from USB stick is actually
> safe in the face of suspend/resume.

I would have expected the same, but in practice it seems to work at
least for a few suspend/resume cycles. Contrast that with a)
suspend/resume not working at all for external SD cards on XO-1 and
XO-1.75 and b) me having disabled aggressive suspend/resume on XO-1.5
because the SD card wasn't entirely reliable across suspend/resume
either.

Sascha

-- 
http://sascha.silbe.org/
http://www.infra-silbe.de/
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