Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Icedove/31.8.0
I found out that one of the flash drives I was using was causing grub to
hang while trying to boot. Using another flash drive I am able to boot
the trisquel installation image. The Debian 8 installation image did not
load as nicely, I had to specify the kernel and ramdisk in the grub
command line, but it did boot. Strange that the first flash drive I used
did not work though, as I used the exact same commands to prepare both.