Comment 560 for bug 1734147

@fardin

I'm no expert on the grub terminal, but you should be able to access all the attached devices even if you couldn't boot from them. There's maybe a command that lists all the partitions, but I was locked out of using modules thanks to SecureBoot. So I used the following method;

The device id (hdn,m) represents drive number 'n' and partition 'm'. So starting with drive 0, partition 1, try 'cat (hd0,1)/etc/issue'. If you get a 'file not found' error increment the partition, e.g. 'cat (hd0,2)/etc/issue'. If you get a 'drive not found' error increment the drive number and reset the partition, e.g. 'cat (hd1,1)/etc/issue'. Once you find the id that returns something ('Ubuntu 18.04 \n \l', I'm guessing in your case), continue onto step three.

This is the brute force method, but you can probably calculate the right drive number base on the number of devices on the laptop (0=Boot device (USB), 1=HDD, etc.). The partition number will be the partition of the root filesystem '/' where you installed. So, best guess for you is (hd1,2). If that doesn't work you'll have to use the brute force method. If *that* doesn't work, then I'm afraid I'm at the limit of my knowledge. Maybe some research into the grub terminal will help you figure out if you can access and boot from the installed drive. It should be possible based on my experience.