I forgot to add that the mainboard did not boot when I built the PC. It would only boot once when I cleared CMOS, and then never more until I cleared it again. I could fix it by downloading a BIOS image of a newer version from asus and flashing it (with a tool called EZ flash, I think, which was in the factory BIOS). Now it boots fine. I tried flashrom -r file.rom and it produced a file of the same size as the downloaded BIOS image ( 1 megabyte) but diff says the binary files differ. I'm not sure whether this means flashrom is not reading the BIOS 100% right or it's just normal because some parts of the file don't get copied to EEPROM or something...
Where do you get your spare EEPROMs ?
I've tried a couple of local electronics parts shops in Barcelona, and they hardly knew Macronix. They couldn't find any MX25L parts listed. I'll try again, I guess...But maybe I should go somewhere else ?