[ubuntu-za] 10.10 Update has overwritten Grub menu?

[vincent]

I did an update, a large one, of a new 10.10 install yesterday. On the
same disk is 10.04 which was in the Grub menu before the update. After
the up date it's gone.
I allocated one partition to boot and separate partitions for 10.10 &
10.04 root, etc & var.(each their own)
Was a common boot partition for both OS wrong and is there a way to make
right without a re-install of 10.04?
I would hate to loose almost 400MB of download time. 

Vince