I have tried to flash an Asus M2N-MX board, and it failed (if I think it well it needs board enable patch). The chip is a SST49LF040B as the flashrom detected. (Checked physically)
Product page can be found here: http://www.asus.com/Motherboards/M2NMX/
Latest BIOS can be found here: http://dlcdnet.asus.com/pub/ASUS/mb/socketAM2/M2N-MX/M2NX1004.zip
I have forgotten to save lspci and superiotool logs, let me know if it needed.
Thank you for your help in advance!