[HH] anyone have experience with fake flash (microSD) memory?

[Bill Bogstad]

On Tue, Jul 15, 2014 at 3:09 PM, Tom Metro <tmetro+hhacking at gmail.com> wrote:
> Bill Bogstad wrote:
>> Anybody want a "fake" SD card to play with?
>
> Don't you have a use for an 8 GB card? (Put a sticker on it with the
> correct capacity to remind you.)
>
> Or do you not trust the altered firmware, even for use within its real
> capacity limits?

Would you?   Here is the (more informative) output of the f3read command
scanning the 1GB files created by the h2testw program:

f3read  /media/BECCAS
                  SECTORS      ok/corrupted/changed/overwritten
Validating file 1.h2w ... 2090790/     6362/      0/      0
Validating file 2.h2w ... 2086366/    10786/      0/      0
Validating file 3.h2w ... 2096430/      722/      0/      0
Validating file 4.h2w ... 2096986/      166/      0/      0
Validating file 5.h2w ... 2097152/        0/      0/      0
Validating file 6.h2w ... 2097152/        0/      0/      0
Validating file 7.h2w ... 2097152/        0/      0/      0
Validating file 8.h2w ... 1672789/   424363/      0/      0
Validating file 9.h2w ...       0/  2097152/      0/      0
Validating file 10.h2w ...       0/  2097152/      0/      0
Validating file 11.h2w ...       0/  2097152/      0/      0
Validating file 12.h2w ...       0/  2097152/      0/      0
Validating file 13.h2w ...       0/  2097152/      0/      0
Validating file 14.h2w ...       0/  2097152/      0/      0
Validating file 15.h2w ...       0/  2097152/      0/      0
Validating file 16.h2w ...       0/  2097152/      0/      0
Validating file 17.h2w ...       0/  2097152/      0/      0
Validating file 18.h2w ...       0/  2097152/      0/      0
Validating file 19.h2w ...       0/  2097152/      0/      0
Validating file 20.h2w ...       0/  2097152/      0/      0
Validating file 21.h2w ...       0/  2097152/      0/      0
Validating file 22.h2w ...       0/  2097152/      0/      0
Validating file 23.h2w ...       0/  2097152/      0/      0
Validating file 24.h2w ...       0/  2097152/      0/      0
Validating file 25.h2w ...       0/  2097152/      0/      0
Validating file 26.h2w ...       0/  2097152/      0/      0
Validating file 27.h2w ...       0/  2097152/      0/      0
Validating file 28.h2w ...       0/  2097152/      0/      0
Validating file 29.h2w ...       0/  2097152/      0/      0
Validating file 30.h2w ...       0/  2097152/      0/      0
Validating file 31.h2w ...       0/  2097152/      0/      0
Validating file 32.h2w ...       0/   479232/      0/      0

  Data OK: 7.79 GB (16334817 sectors)
Data LOST: 23.44 GB (49156127 sectors)
           Corrupted: 23.44 GB (49156127 sectors)
    Slightly changed: 0.00 Byte (0 sectors)
         Overwritten: 0.00 Byte (0 sectors)
Average reading speed: 18.80 MB/s

====

You will notice that there are errors even in the first
8Gig of data written.   Without considerably more testing,
I have no idea what the firmware is going to do.   It would
still think that it has more capacity then is actually there.
I would be doing the equivalent of "short stroking" a
hard drive.   Could it start trying to do wear leveling
to flash that isn't actually there?  No idea and since I have
no idea what the failure modes are likely to be I'm not going
to depend on it for real data.   Besides, it is probably only worth
$5 as a 8GB SD card.   I can't justify the time it would take to
figure out if it is still usable.   It was only because I cared about
possibly losing data that I tested it at all.   Unfortunately, this
probably means that I will have to test all similiar purchases
in the future.  At least it won't take as long as it does to write/read
a 4TByte hard drive.

Bill Bogstad