I'm currently running a Linux Ubuntu installation on my laptop, and we are doing CTF's at school so I need to have Kali available.
However, I also need to customize my Kali (for preference) so I want to be using a USB with a saved installation of Kali. When I tried installing it, it said that it was the only Debian installation on the system, and was wondering if I wanted to save the GRUB-loader on master (HD ?). I was very unsure what to do so I said no for safety of my Ubuntu installation. However when I restarted it wouldn't load Kali.
Do I save GRUB on the same hard disk on which the Ubuntu installation is (the one inside the laptop)? Or should it be on the USB stick with the rest of the Kali installation? If so, what might I be doing wrong.