I've solve this issue for me by NOT using unetbootin to create the installation media but using dd to write it directly to the usb-stick-device-file (ignoring partitions) [or a gui tool that does exactly that like the linux mint usb image writer]
I've solve this issue for me by NOT using unetbootin to create the installation media but using dd to write it directly to the usb-stick- device- file (ignoring partitions) [or a gui tool that does exactly that like the linux mint usb image writer]