unetbootin and dd command does not work when booting the usb, stuck on black screen with underscore

after creating a live usb with kali linux, both "dd" command and "unetbootin", the USB does not boot in my other computer in which i have kali linux installed as well. When I select the USB from the boot menu and load it, it stays stuck in a black screen with a little underscore blinking, i've looked everywhere in goolgle, blakcmoreops, and well it seems that no one have any answers. i have previously tried something in where some files from my computer (running kali) in the boot folder had to be copied to the root of the usb in order to make it boot and it actually worked but i totally forgot how it was done or what files had to be replaced.