Run OFW heat spreader test

Sridhar Dhanapalan sridhar at
Mon Jan 23 01:32:05 EST 2012

On 23 January 2012 17:20, James Cameron <quozl at> wrote:
> I thought you were doing this test to detect early units that may have
> a failed heat spreader, and you were doing it at the time of reflashing
> because that's when you had some control.

Yes, that's the primary reason. Our initial batch of XO-1.5s have an
inefficient heat spreader. They've been burning out, and replacing the
motherboards is getting expensive and time consuming. We'd like to
detect potentially faulty units early, and recommend a heat spreader
change for them.

As a thought - maybe we should be identifying the serial number as well?

> I don't think it is worth doing this test for the purposes of flashing
> the XOs.  The built in throttling will work fine.  If the heat spreader
> is dodgy, you'll either get a hang during fs-update or it will take much
> longer.

Hangs are annoying and don't provide any useful feedback to the user.
It might be true that the XO can't get damaged from flashing, but the
symptoms at runtime are random and are difficult to diagnose. I think
that forcing a heat spreader test can provide a warning to the user
and allow them to do something before any damage or annoying behaviour
can begin.

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