Tails Installer should work as non-root outside of Tails

As of today, the installer requires root to be executed and access disks in Debian Jessie.

'/sbin/sgdisk', '--attributes=1:set:0', '--attributes=1:set:2', '--attributes=1:set:60', '--attributes=1:set:62', '--attributes=1:set:63', '/dev/sdb']
Problem opening /dev/sdb for reading! Error is 13.
You must run this program as root or use sudo!

See #9574 (closed) for initial test and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=788662 “Logged-in user no longer granted permission to removable disks”

Feature Branch: liveusb-creator:feature/jessie+9594-non-root

Parent Task: #8556 (closed)

Related issues

• Related to #9748 (closed)

Original created by @u on 9594 (Redmine)