Hi, please ask on the flashrom mailing list or in the IRC channel. Make sure to mention the board vendor and name, and post the output of "flashrom -V", preferrably using the latest flashrom version (built from source, or from Debian unstable which is pretty recent).
In general: the file size _must_ match, so if your current BIOS is 1024KB, the new one you want to flash must also be 1024KB. But please check back on the mailing list or IRC for more help and information, don't flash anything if you're not sure it'll work.
Thanks, Uwe.