Identifying counterfeit microSD cards on a Beaglebone Black

[Luiz Otavio O Souza]

On 19 March 2017 at 18:45, Dr. Rolf Jansen wrote:
> Am 18.03.2017 um 21:30 schrieb Dr. Rolf Jansen:
>> Am 18.03.2017 um 16:07 schrieb Ian Lepore:
>>> On Sat, 2017-03-18 at 15:03 -0300, Dr. Rolf Jansen wrote:
>>>> Am 18.03.2017 um 12:30 schrieb Warner Losh:
>>>>>
>>>>> On Sat, Mar 18, 2017 at 8:44 AM, Dr. Rolf Jansen
>>>>> wrote:
>>>>>>
>>>>>> I bought a 16 GB microSDHC SanDisk chip rated at 4 MB/s write
>>>>>> speed for use with my Beaglebone Black.
>>>>>>
>>>>>> The internal flash offers practical write speeds in the range of
>>>>>> 2 to 3 MB/s when copying data to it from a NFSv4 volume depending
>>>>>> on the size of the files being copied. Executing the same copy
>>>>>> operation with said microSDHC card as the target I see only 0.1
>>>>>> to 0.2 MB/s (less than 1/10).
>>>>>>
>>>>>> I suspect now that I got a counterfeited card. Before I dump it,
>>>>>> I would like to run a definitive non-destructive test, preferably
>>>>>> on the Beaglebone Black, and I would like to ask you for
>>>>>> suggestions.

[picking a random message to reply]

I just saw an email from SanDisk support (whatever this means) where
they claim the only supported model for this kind of use is the
high-endurance series:
https://www.sandisk.com/home/memory-cards/microsd-cards/high-endurance-microsd

This same email says that running any kind of OS in any of the other
card models automatically breaks the warranty.

HTH,
Luiz