Hello to all..
I had similar problem with the grub not finding correct partitions to boot the ram session.
The problem was that i had assigned labels to the partions and the script used those labels instead of uuids as supposed to.
To fix the problem I changed the lines that set ROOT_UUID and BOOT_UUID from:
sudo blkid -o value $ROOT_DEV | head -1
sudo blkid -o value $BOOT_DEV | head -1
That should get uuid even if label is set or not.
sudo blkid -o value -s UUID $ROOT_DEV
sudo blkid -o value -s UUID $BOOT_DEV
I haven't tested without the labels, though.
Nice script by the way. I was in process of making something similar to use with my nas system before I found this script.
The main point for me with this script is that i can have non-persistent system to play with and to save my all ready worn out hdds of unnecessary read/writes.