So I got a new laptop at work and instead of creating a dual boot system, I bought a 256 GB USB drive and permanently installed Ubuntu 18.04 on it. To boot it, I now just hit F12 during boot (Dell machine) and select the right USB partition. That way I can use my laptop for personal use without storing any data on the on-board hard drive or leaving any other kind of trace.
It has been awesome when it worked, but that is the issue. Many times, including tonight, the boot process will stall at "Loading initial ramdisk" and then nothing happens besides laptop and USB drive getting pretty warm.
Strangely enough, the problem seems to occur rather randomly as I sometimes could boot Ubuntu without an issue the next morning even if it didn't work the night before... I have looked at ways to repair the GRUB on the USB drive using a Ubuntu LiveCD from a second USB drive, but the instructions are not detailed/straightforward enough for me to be successful as it involves editing grub-mkconfig and grub.cfg somehow.
Did anyone have the same issue with an Ubuntu installation on an external USB drive? Can you point me to detailed instructions that let me fix this using a LiveCD?