Hi Hervé,
I noticed you wrote about your flashrom experience at http://www.hmarcy.com/2009/04/how-to-flash-the-bios-of-your-shuttle-barebone... and it seems you have a pretty rare SN68PTG5 http://www.shuttlecomputer.de/desktopdefault.aspx/tabid-72/169_read-14289/ board with MCP67 chipset and LPC flash.
Could you please download latest flashrom from subversion (see http://www.flashrom.org/Downloads for instructions) and run flashrom -V (which shouldn't modify your flash in any way, it just dumps info about it) and then send the output as reply-all to this mail so it ends up on the flashrom mailing list? (You can also reply privately to me if you don't like mailing lists.)
We're trying to improve support for the MCP67 chipset, and part of it depends on knowing whether LPC or SPI flash is attached. Your Shuttle board seems to be the perfect candidate to determine this.
Thank you.
Regards, Carl-Daniel