Create Bootable Flash Drive

Create via terminal

Display List of Hard Drives

lsblk

Copy ISO onto a flash drive

TIP: Before executing the command below you may want to format the disk but not create a volume. I didn’t format it once and it wrote to “cache” and I had a very hard time knowing when it was done actually writing to the drive. I tried safely remove be eventually just gave up and pulled the drive out and then formatted it so the command returning would better sync with completion of copy.

WARNING: Be very careful not to copy to root drive
NB: Takes a while with no feedback, until fail/pass

cp debian.iso /dev/sdX

Create via GUI

Ubuntu has instructions on their website, which I’ve tried up to the part of loading onto the flash drive.

Relevant section copied below in case their site “goes away” (or gets relocated or reorganized or restructured or otherwise cannot be found anymore).

1. Open the Disks application. You can find it in the applications menu or by searching for “Disks”.
2. Insert your USB stick. It appears in the sidebar. Select it there.
   WARNING: Make sure to select the USB stick and not the disk with your running system. Both are listed.
   
3. Close all applications that access files or folders on the USB stick, including the file browser.
4. In the Disks window header, click Drive Options (⋮) and select Restore Disk Image…
   
5. Next to Image to Restore, select the downloaded Ubuntu image file.
6. Click Start Restoring… and confirm. The application asks for your password.
   
7. A progress bar appears while Disks is writing the image.
   
8. When the progress bar finishes, click Eject this disk (⏏).