Since version 7.0 of wheezy, the debian installer has had this problem.
The debian installer in guided partitioning mode does NOT automatically
add the bootable flag to the appropriate partition. This can result in
unbootable systems, especially for beginners.

This should be corrected in wheezy and beyond.

Andres Cimmarusti <acimmarusti@gmail.com> (2013-12-24):

Isn't this flag supposed to be more or less decorative these days?

(IOW: what's your particular setup, why does it need this flag?)

Mraw,
KiBi.

Quoting Andres Cimmarusti (acimmarusti@gmail.com):


And what do you propose for this? :-)

I'm always working with old computers. They don't have a separate EFI
partition (most of them can't handle it anyways) and usually I choose
to install GRUB in the root partition, thus I need to make it
bootable. I assure you there's nothing decorative about it in these
systems. When I first tried wheezy in one of these computers, I kept
getting unbootable installations, and finally I saw that ticking on
the bootable flag did the trick.

I propose this be re-enabled by default on the guided partitioning if
the debian installation media is NOT booted in EFI mode. Unless I'm
grossly misunderstanding the issue as I explained above.

Quoting Andres Cimmarusti (acimmarusti@gmail.com):

Eagerly waiting for the patch....

So the problem is the installation of GRUB into the root partition
instead of the MBR. Which is only known at the end of the installation.

Kind regards
Philipp Kern