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/etc/apt/sources.list
deb http://mirrordirector.raspbian.org/raspbian/ wheezy main contrib non-free rpi
/etc/apt/sources.list.d/raspi.list
deb http://archive.raspberrypi.org/debian/ wheezy main
/etc/apt/sources.list
deb http://mirrordirector.raspbian.org/raspbian/ jessie main contrib non-free rpi
/etc/apt/sources.list.d/raspi.list
deb http://archive.raspberrypi.org/debian/ jessie main
Install the package rng-tools and add to /etc/modules:
bcm2708-rng
Add this to /boot/config.txt
max_usb_current=1