I run Debian Wheezy alone on my PC and I recently copied the root partition to another with rsync as I found that worked well (I also know about dd and ddrescue but they leave unusable space on the new partition). I generated a new random UUID for the new partition with sudo tune2fs -U random /dev/hda9 and also updated fstab / and /home entries.

Then as I know so little about GRUB I used a gui (GRUB Customizer) to probe for the new OS and add an entry to GRUB and the MBR -it makes an /etc/grub.d entry then updates GRUB.

On startup, the GRUB list contains the new OS (on sda9) but it boots the first OS (which I copied from -sda5).

/boot/grub/grub.cfg contains the new debian OS but it looks like this

set root='(hd0,msdos9)'  
search --no-floppy --fs-uuid --set=root 64662470-0e58-4dfd-90ac-43227d773556  
linux /boot/vmlinuz-3.2.0-2-amd64 root=UUID=cc3bca0d-aee4-4b9c-95c2-57212cc36d4d ro quiet  
initrd /boot/initrd.img-3.2.0-2-amd64

the 1st uuid is of sda9, but the 2nd uuid there is of sda5. I can change the 2nd uuid at startup (with E) and it boots sda9.
So how can I get grub.cfg corrected so that the sda9 GRUB list entry boots from sda9 permanently?