Migrating XO-1.75 to device tree - upgrade considerations

[Sridhar Dhanapalan]

On 23 August 2012 09:00, Jerry Vonau <jvonau at shaw.ca> wrote:
> On Wed, 2012-08-22 at 09:53 -0600, Daniel Drake wrote:
>> Either way, I don't quite understand the situation involving the
>> firmware here. (Maybe until now) there has been no driving need to
>> upgrade firmware when upgrading OS releases - it can be done before,
>> after, 3 weeks after, doesn't make a big difference.
>
> 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.

We also wanted an easy way to get NANDblaster-compatible firmware out
to all of our XOs in the field. As the first adopters of the XO-1.5,
we had many units that could not receive a NANDblaster signal.

We don't issue firmware updates very often at all.

>> Or is there a
>> reason I'm missing for why you go to special lengths to make sure the
>> firmware upgrade is done first?
>>
>
> 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 use charging racks for classroom sets, not individual AC adapters.
It is not practical to boot/use the XO while it is plugged in. Hence,
firmware updates cannot occur if AC is required. Our workaround is to
remove the AC check and institute a battery check. We understand that
there are risks involved in this (e.g. the reported battery state may
be different from the actual state), we decided that the benefits
outweigh the risks.

Sridhar