On Wed, Apr 01, 2015 at 06:52:34AM -0400, Bob Ammerman wrote:
> > > Yeah, there's still work to do. Getting it going with files in a
> > > different location is encouraging. [...]
>=20
> Could it have something to do with the data's alignment within a
> write block on the flash?

Yes, good point.

Although alignment is almost entirely uncontrollable.

Erasing the device may be useful.  In theory that may force all
alignments back to zero, because all blocks will have been released.
But it is difficult to be sure unless you have the source code for the
FTL, or have probes between the FTL and the array.

Erasing the device means sending the ERASE command sequence for the
whole block range of the device.  CMD32 with the first block number.
CMD33 with the last block number.  Then a CMD38 with wait for busy.

Erasing the device does NOT mean writing zero blocks, or reformatting
the filesystem.  All that does is allocate blocks from pages in the
flash array.

Implementation references for Open Firmware:

http://dev.laptop.org/git/users/quozl/openfirmware.git/.git/tree/dev/mmc/sd=
hci/sdhci.fth#n1139

User guidance:

http://wiki.laptop.org/go/Firmware/Storage#How_to_quickly_erase_everything

--=20
James Cameron
http://quozl.linux.org.au/
--=20
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