I did something similar, but I didn't add the prober. First, I used the sudo command:
sudo nano /etc/default/grub
You'll see the following menu:
I then changed the menu style from "hidden" to "MENU" (all caps)
Then changed the GRUB_TIMEOUT from "0" to "10"
It should look like this:
Hit Cntrl+O, Enter, Cntrl+X.
I then used the following sudo command to update the GRUB menu:
sudo update-grub
Restart the computer and you should see the Grub menu without any further issues.
I know this topic has already been resolved. I was simply offering an alternative solution.