Back up of the "Factory Bad Block Table" BBT, needed or a waste of time?
laforge at openmoko.org
Sun Jul 29 08:41:41 CEST 2007
On Sat, Jul 28, 2007 at 02:46:24PM +0200, Visti Andresen wrote:
> I'm probably going to receive my Neo next Monday (the joy).
> The gpsd should be backed up by the procedure in:
this is not present on phase-1 handsets and only accidentially ended up
on the GTA01Bv4 that were sent to phase-0 developers before. I've
updated the wiki accordingly.
> and inside the bad block table (BBT), I guess that the BBT isn't located
> inside the 4. partition and therefor not backed up?
well, technically it is in the rootfs partition... but in blocks that
are marked as bad blocks ;) so depending on the method of your backup,
you will either have it or not.
> Is it necessary to back up the BBT alt all?
Depends on what you want to do. It makes sense. In fact, I have asked
our production software team multiple times to store the bad-block
information at the factory for each device, so we can theoretically
restore that information for any given device. I don't know the status
of it, though.
> Can the "factory BBT" be recreated using JTAG?
not if you erase all inline and OOB data by something like 'nand scrub'
of u-boot. This will erase everything!
> or has the factory used a special kind of "magic" when
> establishing the BBT?
no. it just scans the nand flash for factory bad block markers (see
nand data sheet) and creates its own table (for faster access and as a
- Harald Welte <laforge at openmoko.org> http://openmoko.org/
Software for the world's first truly open Free Software mobile phone
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