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

[Adam Holt]

From: Paul Fox <pgf at laptop.org>
Date: Fri, Feb 7, 2014 at 6:41 PM
Subject: Re: is rolling back firmware dangerous? (on XO-1s especially)
To: Adam Holt <holt at laptop.org>
Cc: support-gang at laptop.org

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.

but why do you think it's necessary?

 >
 > 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.)

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

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.

=---------------------
 paul fox, pgf at laptop.org


-- 
Unsung Heroes of OLPC, interviewed live @ http://unleashkids.org !
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