grub-mkconfig os-prober did not update UUID

[Claude Robitaille]

Hi,

I am copying a root FS on a different partition, hence the UUID needed to boot 
from that new partition is different. I am running grub-mkconfig on the main 
partition (with os-prober installed and the new partition mounted).

The resulting /boot/grub/grub.cfg is perfect; the new partition menuentry is 
created as expected in the /etc/grub.d/30_os-prober section. Except for one 
glitch: every UUID referenced in that menuentry were updated EXCEPT the most 
important one; the linux kernel command line argument root= still has the 
original UUID. Manually updating it prove that the menuentry is otherwise Ok 
(by booting using it).

Is this a bug or an intended behaviour?