Quote Originally Posted by CrazyNutz View Post
There is a checksum of some value in each bios. If any changes are made in the bios this checksum must be recalculated.

For examples sake lets say its originally dec "78", if you make a change and recalculate the checksum, it will now be let say "107"

In some bioses (probably just uefi) if the original checksum "78" has been recalculated to something else, the nvidia driver may detect this and fail to load "no supported hardware detected" < some message like this.

This may be an attempt by nvidia to stop bios mods, my best guess anyhow.

So when you Preserve_Original_Checksum = 1, after a mod kgb forces the checksum to recalculate to the original value "78".
It does this by changing values in the padding (unused) sections of the bios so the checksum will = 78.
Got it. But what I don't understand is what would be the disadvantage if you keep Preserve_Original_Checksum to 1 all the time even when modding non-UEFI BIOS? Is there some disadvantage when recalculating the checksum by using the original value?