Problem with alt_flash_open_dev

Hi all,

i have question about open flash memory (fd = alt_flash_open_dev("/dev/epcs_flash_controller_0");).

When i restart my board with EP3C25 and the bitstream is loaded from epcs flash eprom or when i download bitstream to the fpga from Programmer and after this i run program, where i try to open flash eprom, it failed (fd is Null). But when i restart this program again, open flash is ok and next code of program run well. Where could be the problem ?

When i find, what happens on nCS pin, i see (on oscilloscope), that after downloading sof from flash (turn off/turn on the board) or from Programmer, the nCS is on "0" / GND and after this, when i run the program which failed in the first, the nCS goes to "1" high and after this when i start (in second time) the program it run well.

Some idea, where is error ?

Thank you.

Jan Naceradsky