Unable to find the name of CFI flash while running memory test template.

Hello guys!

I'm trying to execute the memory test template. I select the option to test flash.

I have checked in the system.h file that the name of the flash is /dev/ext_flash. But when I type in the same name in the nios console, it shows an error

saying : could not open "/dev/ext_flash"

any idea how to eliminate this error?

Thanks in advance.. any advice is welcome.