AT25F512 recognized as AT25F1024

[Chi Zhang]

Recently I got an AT25F512(no A) chip from my old nVidia Geforce FX 5200 card. 
However, flashrom seems to recognize it as AT25F1024:

flashrom -p serprog:dev=/dev/ttyACM0:4000000,spispeed=1000000 
flashrom v0.9.6.1-r1658 on Linux 3.2.0-39-generic (x86_64)
flashrom is free software, get the source code at http://www.flashrom.org

Calibrating delay loop... OK.
serprog: Programmer name is "serprog-STM32VCP"
Found Atmel flash chip "AT25F1024(A)" (128 kB, SPI) on serprog.
No operations were specified.

The detailed log with -VV canbe found at: 
http://paste.flashrom.org/view.php?id=1568

[Stefan Tauner]

On Tue, 02 Apr 2013 20:32:44 +0800
Chi Zhang  wrote:
> Recently I got an AT25F512(no A) chip from my old nVidia Geforce FX 5200 card. 
> However, flashrom seems to recognize it as AT25F1024:
>
> flashrom -p serprog:dev=/dev/ttyACM0:4000000,spispeed=1000000 
> flashrom v0.9.6.1-r1658 on Linux 3.2.0-39-generic (x86_64)
> flashrom is free software, get the source code at http://www.flashrom.org
>
> Calibrating delay loop... OK.
> serprog: Programmer name is "serprog-STM32VCP"
> Found Atmel flash chip "AT25F1024(A)" (128 kB, SPI) on serprog.
> No operations were specified.
>
> The detailed log with -VV canbe found at: 
> http://paste.flashrom.org/view.php?id=1568

Thank you very much for this information. I had to guess the device IDs
because they are not mentioned in the datasheet.
The AT25F1024A has 0x60, the AT25F512A has 0x65, the AT25F025B has
0x6500... but apparently assuming at least some sanity has failed to
reflect the truth.

So, according to your verbose log your AT25F512 has the same ID as the
AT25F1024A (according to its datasheet). *sigh*
Before I'll make some changes to the code I'll try to find someone with
a AT25F1024 chip to test.

[Chi Zhang]

在 2013年4月2日 星期二 15:19:25，Stefan Tauner 写道：
> Thank you very much for this information. I had to guess the device IDs
> because they are not mentioned in the datasheet.
> The AT25F1024A has 0x60, the AT25F512A has 0x65, the AT25F025B has
> 0x6500... but apparently assuming at least some sanity has failed to
> reflect the truth.
>
> So, according to your verbose log your AT25F512 has the same ID as the
> AT25F1024A (according to its datasheet). *sigh*
> Before I'll make some changes to the code I'll try to find someone with
> a AT25F1024 chip to test.

Bought an AT25F1024(without A) recently and tested.
http://paste.flashrom.org/view.php?id=1620

Found a PCN from Atmel, stating that AT25F512's device code is 0x60, and the 
new AT25F512A's is 0x65:
http://www.baite.com.hk/uploadFiles/service/SB_serial_mod_PCN_25F512.pdf

Another interesting thing is that my AT25F512 can actually hold 128KBytes of 
data. I generated the test data from /dev/urandom and confirmed that it 
contains no repetitive patterns with lzma -9 (a fake 128KB "random" data file 
made up with two 64KB ones with same content can be compressed into ~65KB 
while mine can not). All bytes seems to be functional, I had zeroed out and 
erased the whole chip and I got 128KB 0x00 an 128KB 0xff. After a power cycle 
the random data written to the chip can be preserved.

Maybe some day I will buy a new & original AT25F512 and test whether it can 
hold 128KB data.

Photos of the chips:
https://dl.dropboxusercontent.com/u/4389799/P1130184.JPG
https://dl.dropboxusercontent.com/u/4389799/P1130188.JPG

[Stefan Tauner]

On Fri, 19 Apr 2013 12:32:15 +0800
Chi Zhang  wrote:
> 在 2013年4月2日 星期二 15:19:25，Stefan Tauner 写道：
> > Thank you very much for this information. I had to guess the device IDs
> > because they are not mentioned in the datasheet.
> > The AT25F1024A has 0x60, the AT25F512A has 0x65, the AT25F025B has
> > 0x6500... but apparently assuming at least some sanity has failed to
> > reflect the truth.
> >
> > So, according to your verbose log your AT25F512 has the same ID as the
> > AT25F1024A (according to its datasheet). *sigh*
> > Before I'll make some changes to the code I'll try to find someone with
> > a AT25F1024 chip to test.
>
> Bought an AT25F1024(without A) recently and tested.
> http://paste.flashrom.org/view.php?id=1620
>
> Found a PCN from Atmel, stating that AT25F512's device code is 0x60, and the 
> new AT25F512A's is 0x65:
> http://www.baite.com.hk/uploadFiles/service/SB_serial_mod_PCN_25F512.pdf

Oh that's very interesting. Thanks a lot for digging this up!
> Another interesting thing is that my AT25F512 can actually hold 128KBytes of 
> data. I generated the test data from /dev/urandom and confirmed that it 
> contains no repetitive patterns with lzma -9 (a fake 128KB "random" data file 
> made up with two 64KB ones with same content can be compressed into ~65KB 
> while mine can not). All bytes seems to be functional, I had zeroed out and 
> erased the whole chip and I got 128KB 0x00 an 128KB 0xff. After a power cycle 
> the random data written to the chip can be preserved.

That's very odd. Maybe they just relabelled the AT25F1024s as AT25F512?
I am only aware of (non-functional) fakes the other way round (and you
too obviously ;)

I'll change the ID of AT25F512 and commit that later. Thanks a lot for
your efforts.