What the fuck is SBAT, why did it break your dual-boot setup, it's not strictly my fault but if you need a scapegoat whatever: https://mjg59.dreamwidth.org/70348.html
@mjg59
So it's not just dual boot, it's anyone who uses an old version of Grub, even if they are only using it to boot Windows for some reason. And since Microsoft doesn't ship Grub, the exception (had it worked) would need to be for anyone using the software the update was intended to block, basically making the update useless.
@leeloo The boot path for booting Windows from grub isn't really affected by this for extremely convoluted reasons, except in cases where someone's doing it maliciously
@mjg59
If we define maliciously by whether or not the exact same thing is done by the owner of the computer or someone else, that is logically impossible.