found a fix for the mangled screen graphical error while trying to install kali-linux via usb live. i install kali to an external hard drive today DESPITE not being able to see what i was doing by plugging in a set of head phones and using the voice synthesizer. and am currently posting this from said machine so yes its possible. you can create a basic partition unless you already have one, during the install. you'll need to know the scsi of the disk your going to partition. during the partition part of the install. pick your partition. then wait and listen to the options your going to want the last option to continue the install after you pick the partition of your drive. once the install is done your computer will restart and you'll want to pick the linux gnu with kali linux - (whatever your linux is. mine was 2018) i think it was in advanced options) remember this is AFTER the install is done on your disk AND your computer restarts. give it a try, it was the only fix i could find. my grub shell would not let me do nomodeset, it wouldn't let me change the resolution. if this is not for you, you can but a usb with at least 8 gigs and do a usb with persistence. that way it saves what you do during a session. this will allow you to update and keep grub/grub2 shell/prompt. then you can return to the install menu and hopefully do something with it. unfortunately this was not an option for me considering by usb was only 4gig. i will check this periodically throughout the week if you have questions i will try to help but it could be awhile before i respond