Is the Rock 64 something strange?

[kometchtech]

No.

... always suspect a bad, cheap, defective or fraudulent SD card;  its that simple.

We recommend Samsung 32G Class 10 Evo Plus cards !   Also, you can test your cards for fraud;  there are many fraudulent cards out there;  please read this link.

Thanks for the reply.

Is Samsung EVO plus? If EVO is useless, I feel pretty severe with regard to the corresponding microsd.
Let's buy Evo plus for the time being and try it.

Best regards.

Evo is OK but beware there are a huge amount of counterfeits on offer or sub standard product.
Evo just slower and the price saving isn't really worth while but that card you have could be defective.
Have you tried writing an number of large files to it and used it on something else?

Thank you for reaction.

According to the information you hear from Samsung EVO, there seems to be various problems. Certainly, silicon power is different, but for EVO it is purchased from overseas and imported.
I tried to check with f3 tool heard from MarkHaysHarris777, but the microsd card itself seems not to be damaged (the file system was not broken). However, the write speed is 10MB, which seems to be just like Guaranteed by Class10 for the time being.

Let's order EVO plus at a domestic store for the time being.
So I will check again.

Once you have obtained EVO plus you will contact the results.

Thank you for your advice.

Best regards.

It could be that Rock64 maybe a bad one but Flash and SD is so dodgy at the moment.
I got 2 Sandisk Cruizer Blade 32GB good price off ebay.
Packing and product looks perfect but complete rubbish and not even sure if its just a bad batch from Sandisk.

Oh ...

Anyway I bought I also from ebay. It was selected in only price.
 
We will use what we purchase from stores that do not have problems, such as authorized distributors, to use for this product.
It seems that that person is less likely to be in trouble.

Best regards.