The user is "grub" and the password was randomly generated when Trisquel was
installed. You can read it at the very end of /etc/grub.d/01_PASSWORD.
Instead of learning that password, I suggest you to get rid of it... since it
"only serve[s] to make it difficult to recover broken systems".
Both kernels are 100% free software (the blobs in vanilla Linux are removed).
The main difference is the version: the older version, Trisquel's default,
has been more tested but does not have the latest features introduced in
Linux (in particular the latest drivers that support newer
Keep the newer kernels if they better support your hardware! If you added
Jxself's Linux-libre repository (not a manual installation of one .deb
package), then you will get frequent updates: only security updates until the
version stops being supported if you installed "linux-libre-4.9" or
As long as you use newer versions (taken from Jxself's repository) of the
kernel, the older versions will not be used by default because GRUB prefers
the newest version (you can change its configuration or manually boot an
older version from the "Advanced options" of GRUB's menu).
Please show us the output of this command:
$ ls -l /etc/apt/sources.list.d
