MB : Asus P5N7A-VM
old bios vers. : 512
new bios vers. : 519

# flashrom
flashrom v0.9.4-r1455 on Linux 2.6.32-220.2.1.el6.centos.plus.x86_64 (x86_64), built with libpci 3.1.4, GCC 4.4.5 20110214 (Red Hat 4.4.5-6), little endian
flashrom is free software, get the source code at http://www.flashrom.org

Calibrating delay loop... OK.
Found chipset "NVIDIA MCP79".
This chipset is marked as untested. If you are using an up-to-date version
of flashrom please email a report to flashrom@flashrom.org including a
verbose (-V) log. Thank you!
Enabling flash write... This chipset is not really supported yet. Guesswork...
SPI on this chipset is WIP. Please report any success or failure by mailing us the verbose output to flashrom@flashrom.org, thanks!
Mapping NVIDIA MCP6x SPI at 0xf9f80000, unaligned size 0x544.
Please send the output of "flashrom -V" to flashrom@flashrom.org with
your board name: flashrom -V as the subject to help us finish support for your
chipset. Thanks.
OK.
This chipset supports the following protocols: SPI.
Found Winbond flash chip "W25X80" (1024 kB, SPI) at physical address 0xfff00000.
No operations were specified.

Saving old ROM : Succed
Writind new ROM : Succed (no reboot now)
After rebooting it works just fine.

Thx for flashrom utility.