You don't need GUI for this. Actually GUIs in my experience are terrible with
it.
Insert the fat32 formatted USB stick in your laptop and open the terminal and
follow this:
lsblk
look up and not the name assigned to your usb stick. sba is usally your hard
drive, it will be either sdb or sdc. For the arguments, or better yet,
example's sake, say your stick is sdb. For the same reason say your Trisquel
ISO is in ~/Downloads/
To write the ISO on your stick all you need is one single command, one that
has never ever failed me on any hardware and with any ISO:
sudo dd if=~/Downloads/Trisquel_ISO.iso of=/dev/sdb bs=4M ; sync
