Fwd: [support-gang] is rolling back firmware dangerous? (on XO-1s especially)

[Adam Holt]

From: James Cameron <quozl at laptop.org>
Date: Fri, Feb 7, 2014 at 7:17 PM
Subject: Re: [support-gang] is rolling back firmware dangerous? (on XO-1s
especially)
To: "Community Support Volunteers -- who help respond to \"help AT
laptop.org\"" <support-gang at lists.laptop.org>
Cc: Adam Holt <holt at laptop.org>, support-gang at laptop.org

On Fri, Feb 07, 2014 at 06:41:48PM -0500, Paul Fox wrote:
> adam wrote:
>  > I used to do this all the time while testing XO-1s with different
>  > firmwares, but want to check if the _process_ of rolling back firmware
on
>  > XO-1s is dangerous to the machine in general:
>  >
>  > 1) Are there risks to the _process_ of rolling back XO-1 firmware, EG
from
>  > q2f19 to q2e48 (Release 11.3.0) as used by many in Kenya?
>
> no, there are no inherent risks in the process.
>

sometimes a full power removal is necessary; main battery and adapter.

but i agree, within that range of versions there's no problem that i
recall, and i do it still, much more often than you.

> but why do you think it's necessary?

i second the question.  if you think it is necessary then there must
be some legitimate concern rather than some vague fear, and so i want
to hear about it and fix it.

>  > http://wiki.laptop.org/go/Firmware#XO-1
>  >
>  > 2) Separate question: what risks might arise running Release 11.3.0
>  > (required by many in Kenya) with more modern firmware like q2f19?
>
> we tried very hard to make sure that that scenario works correctly,
> but of course not all combinations were (or could be) tested.  [1]
>
> in addition, downgrading the firmware won't downgrade the EC code, so
> the firmware will be running against a newer EC version that it wasn't
> tested with.  we tried very hard to make sure that all EC f/w versions
> were compatible with old firmware and OS, but again, testing all
> combinations would have been impossible.  (note that i don't recommend
> downgrading the EC to address this risk.  the bug fixes added to later
> EC releases are probably worth having.)

actually, on the XO-1, the EC firmware is in the same place as the
host firmware, so it will downgrade the EC firmware if you downgrade
the host firmware.

what paul says in this paragraph above applies to XO-1.75 and XO-4
only.

> summary:  stick with the newest firmware unless you have good reason
> not to.

agree, and reinforce.

if there's any reason why 11.3.0 does not work with q2f19, then i want
to know, and i will try to fix it.

> paul
>
> [1] the converse, e.g. running 13.2.0 on q2e48 is not guaranteed to
> work, and, in fact, may well break things.  that's why new compatible
> firmware comes with each new OS.

agreed.

--
James Cameron
http://quozl.linux.org.au/

-- 
<http://quozl.linux.org.au/>
Unsung Heroes of OLPC, interviewed live @ <http://quozl.linux.org.au/>
http://unleashkids.org !
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