The line of script that checks from the card reading done:

"time -p cp / media/mmc1/test.dat /dev/null"

The virtual device "/dev/null" is a black hole. Where not to save anything, is used to simulate the copy from one point to another point.

In my device returns the following message:

"cp: can create ' dev/null ' : File exists"

in my GNU/Linux the script works perfectly.