You can never truly be sure as it's can't be entirely removed. There has to be a little bit remaining, just the first few modules or the machine will shut down

You can never truly be sure as it's can't be entirely removed. There has to be a little bit remaining, just the first few modules or the machine will shut down after 30 minutes, but the Librem 15 is a beautiful machine and Puri.sm are really awesome.