Comment 57 for bug 1061255

I've reinstalled 12.04, out of curiosity.
Grub:
sudo apt-cache policy grub-pc
grub-pc:
  Installed: 1.99-21ubuntu3
  Candidate: 1.99-21ubuntu3
  Version table:
 *** 1.99-21ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
        100 /var/lib/dpkg/status

And the grub.cfg - booting perfectly into Win7 on the secondary disk.

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os {
        insmod part_msdos
        insmod ntfs
        set root='(hd1,msdos2)'
        search --no-floppy --fs-uuid --set=root 085AFE3C5AFE265A
        chainloader +1
}