On Wed, 13 Aug 2003, Stefan Reinauer wrote:
devbios generally knows how to do this for certain chipsets, including the 440. Unfortunately some mainboard vendors additionaly protect flash write with some undocumented GPIO circuit, so supporting the chipset alone is not enough. There is not much you can do except gnireenigne esrever existing firmware or trying out all possible GPIO lines (and combine them etc) The first is probably illegal in some countries, the second might destroy your hardware, esp. on laptops.
I did in fact try all GPIO combinations on the T23 GPIO lines, as well as on the T22. Interestingly enough, some of them will reset the laptop. But I never found the combination, after much work, that would open up SPD or enable FLASH write. Some of these designers put an extra flipflop in such that the control bits are "sticky" -- you can turn the SPD off, for example, but not back on.
We found out how to do this type of thing on the L440GX, and the hardware was not simple.
ron