Comment 1 for bug 1065261

Colin Watson (cjwatson) wrote :

-w is consistently documented as "write unique sig to MBR *if needed*" (emphasis mine), and the original ChangeLog entry that introduced it said:

- Added test for non-zero signature on MBR-style disks,
  and new -w flag to write a unique signature to the disk if so.

So I think this is an efibootmgr bug for failing to meet its own documentation, and since that documentation happens to describe a much more convenient behaviour, I'm going to fix efibootmgr rather than add some quite complex code to grub-install to parse the MBR.