Windows applications making GRUB 2 unbootable

“If you find that running Windows makes a GRUB 2-based system
unbootable (Debian bug, Ubuntu bug), then I’d like to hear from
you. This is a bug in which some proprietary Windows-based software
overwrites particular sectors in the gap between the master boot
record and the first partition, sometimes called the “embedding
area”. GRUB Legacy and GRUB 2 both normally use this part of the
disk to store one of their key components: GRUB Legacy calls this
component Stage 1.5, while GRUB 2 calls it the core image
(comparison). However, Stage 1.5 is less useful than the core image
(for example, the latter provides a rescue shell which can be used
to recover from some problems), and is therefore rather smaller:
somewhere around 10KB vs. 24KB for the common case of ext[234] on
plain block devices. It seems that the Windows-based software
writes to a sector which is after the end of Stage 1.5, but before
the end of the core image. This is why the problem appears to be
new with GRUB 2.

“At least some occurrences of this are with software which
writes a signature to the embedding area which hangs around even
after uninstallation (even with one of those tools that tracks
everything the installation process did and reverses it, I gather),
so that you cannot uninstall and reinstall the application to
defeat a trial period. This seems like a fine example of an
antifeature…”

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