Since installing F17, GRUB can't find F16 (separate partition)

[JonAllan]

Have installed F17, overwriting Windows. F16 is on the same disk, different partition, and I need to boot into it for a while yet. But F16 does not appear on the GRUB menu installed by F17. From F17 I can access all files, but I still need to run some programs in F16 so need to boot into it. How can I teach GRUB that F16 exists? I enclose output of running "bootinfoscript". F17 is on sda1, F16 on sda6. Thanks for help.

[JonAllan]

I sorted the problem in an amateurish but successful way. I reinstalled Ubuntu 12.4; this produced a GRUB which only showed F16 and Ubuntu. Then from Ubuntu in a terminal I did:
sudo grub-install --recheck /dev/sda
sudo update-grub
This gave me a GRUB with all three operating systems - problem solved.