Migrating XO-1.75 to device tree - upgrade considerations

James Cameron quozl at laptop.org
Wed Aug 22 19:36:30 EDT 2012

On Wed, Aug 22, 2012 at 06:00:21PM -0500, Jerry Vonau wrote:
> Yes it did at one point, way back when sparse support was first
> added to the .zd files in order to gain the speed advantage offered
> the required firmware must be installed first.

That's not how I remember it.  Sparse support worked but generated a
minor warning.  You wanted the firmware upgrade to avoid the warning.
You might instead have suppressed the warning.


> After an OS upgrade we can't expect a teacher to boot each XO with
> an AC adapter plugged-in when there maybe only one adaptor available
> for the class or no AC at all because of the use of alternate
> charging methods.  I wonder how this is handled in other deployments
> that are using solar-panels or hand cranks because there is no AC
> available. We have chosen to have the firmware installed from a USB
> drive as we can disable the AC check, and use the charge level of
> the battery to ensure there is enough power present to ensure
> success with the updating processes with our olpc.fth script.

We know the battery state of charge may be unreliable under certain
conditions, and that's one reason why we also require external power,
as well as a minimum voltage and charge state.

I'm glad you've taken on that risk, but not all deployments have such
a high level of technical support and literacy.

James Cameron

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