zhashfs: write first block last

[Daniel Drake]

On 20 March 2011 11:32, Mitch Bradley <wmb at laptop.org> wrote:
>
>
> On 3/20/2011 6:58 AM, Chris Ball wrote:
>>
>> Hi,
>>
>> On Sun, Mar 20 2011, Daniel Drake wrote:>
>>>
>>> 1. Is this approach a good idea?
>>
>> Sounds great to me.
>>
>>> 2. Are we bothered by a misleading WARNING message appearing at the
>>> end of the flashing process for those running on old/current firmware?
>>> (a firmware update would fix this in future)
>>
>> I expect it'll cause people to report it to us or OLPCA as an error, yeah.
>> Am I right in thinking that a .zd is actually just a signed forth script?
>
> Actually it's the zsp that is signed, as a proxy for the much larger zd.  So
> the patch needs to be in the zsp.
>
> The desire for the patch to apply both in secure and non-secure modes
> greatly complicates the situation.
>
> Maybe we should have a flag day.

To bring this back on-list... (we went off when a private untested
firmware release was posted)

OFW is now fixed in svn (accepts this new format without any confusing
error), a release should be made soon.

As for zhashfs, writing block 0 as all-zero was unnecessary as the
entire SD card gets blanked at the start of fs-update. (tweaked this
locally)

Mitch has provided a code segment for .zsp files that means that users
of old/current firmware will not see the confusing error message (this
includes those who do 4-key reflash). (tweaked zhashfs to insert this)

We haven't addressed the confusing error message for users of
old/current firmware in unsecure mode, but instead we'll rely on
people reading release notes and so on to know to ignore the error
message just once.

I'll do at least one 11.2.0 development release with the new firmware
and "old format" .zd file, before switching to the new .zd format.
Therefore those who keep up with every development build won't see the
confusing error message at all.

details in:
http://dev.laptop.org/ticket/10818

Daniel